bluuebunny/crossref_metadata_2025 huggingface dataset:
Short Term Treatment With Thrombopoietin-Receptor Agonists For Patients With Immune Thrombocytopenic Purpura (ITP) Before Splenectomy
Authors: Kalish Yosef , Spectre Galia , Varon David
Published: October 2019

The thrombopoietin-receptor agonists (romiplostim and eltrombopag) were approved recently as treatments for patients with immune thrombocytopenic purpura (ITP). Splenectomy remains a common second line treatment for ITP with the highest remission rate compared with alternative therapies. It has been reported that splenectomy can be safely performed in patients with a platelet count of 40-50,000 per cubic millimeter but many patients do not reach these values. Intravenous immune globulins (IVIG) are often used before splenectomy in order to increase the platelet count before surgery.

The aim of this study was to determine whether a short course of thrombopoietin-receptor agonists can be used as a reliable and safe treatment to increase the platelet count in patients with ITP before splenectomy.

Between 2010 and 2012, fifteen patients with ITP, all refractory to steroids, were scheduled for splenectomy. Treatment with thrombopoietin-receptor agonists (romiplostim or eltrombopag) was started 3 weeks before splenectomy. Eight patients received eltrombopag at a dose of 50 mg/day orally until 3 days before splenectomy. For romiplostim, a subcutaneous injection of 3 mcg/kg was given weekly to 7 patients. The last injection was given one week before splenectomy. Complete blood count was repeated every week and the dose of romiplostim was adjusted (up to 10 mcg/kg or down to 1 mcg/kg) based on the platelet count increment. Response was defined as a platelet count of 50,000 or more per cubic millimeter.

Mean platelet count before treatment was 11,000±8,000 cells per cubic millimeter. All patients, except one patient on romiplostim, responded to the treatment with a mean platelet count of 74± 25 cells per cubic millimeter on the day of splenectomy (p<0.01). Similar effect was noticed among responders of the two drugs. Four patients from the romiplostim group responded to a 3 mcg/kg dose. Two patients responded to increased doses of 7 and 10 and 10 mcg/kg. One patient did not respond to 10 mcg/kg of romiplostim but later responded to IVIG. The two drugs were well tolerated with no side effects except for mild liver function abnormalities in one patient in the eltrombopag group. No thromboembolic complications or excessive bleeding were reported for these patients.

In summary, we report that a short course of thrombopoietin-receptors agonists can effectively and safely increase the platelet count in steroid resistant ITP patients before splenectomy.

Disclosures:

No relevant conflicts of interest to declare.
Immune-Mediated Activation Of Coagulation In Patients With Stevens Johnson Syndrome/Toxic Epidermal Necrolysis
Authors: Iqbal Omer , Syed Daneyal , Mosier Michael , Malalis Julia , Mata Christine , Lin Amy , Mitchel Nicole , Abro Schurahazard , Hoppensteadt Debra , Fareed Jawed , Bouchard Charles
Published: October 2019

Background

Stevens Johnson Syndrome/Toxic Epidermal Necrolysis (SJS/TEN) are specific drug hypersensitivity reactions initiated by cytotoxic T-lymphocytes. Augmentation of T-cell activation by positive co-stimulation and Major Histocompatibility Complex-restricted presentation of the culprit drug triggers T-cell activation following interaction with T-cell receptors. This T-cell activation results in expression of cytokines including TNF-α, interferon-γ, granzyme B and granulysin from NK cells. Besides their role in causing SJS/TEN, these cytokines cause coagulation activation.

Materials & Methods

Following an Institutional Review Board approved protocol blood samples were obtained from subjects suspected of SJS/TEN and normal healthy volunteers (n=2). Confirmatory biopsies were performed in all SJS/TEN subjects which confirmed SJS/TEN in 4 subjects and were negative in 7 subjects. Cytokine levels were measured using the cerebral II array biochip from Randox Laboratories Limited (Crumlin, UK). Besides cerebral array II, other parameters such as thrombin-antithrombin (TAT) complexes (Dade®, Marburg, Germany), fibrinopeptide A (F1.2, Dade®), plasminogen activator inhibitor-1 (PAI-1, Diagnostica Stago® and STACHROME antithrombin (Stago®), ZYMUPHEN platelet microparticles activity (Hyphen® Biomed (Neuville-sur-Oise, France), and HEMOCLOT protein C (Stago®) were measured using ELISA kits as per manufacturers’ instructions.

Results

Compared to the Normal Human Plasma, the IL-4, IL-6, TNF-α, and MCP-1 levels were increased significantly in biopsy-confirmed SJS/TEN patients (see table). Other parameters measured including IL-2, IL-8, IL-10, VEGF, INF-γ, IL-1α, IL1-β and EGF were not significantly increased. A marked increase in the TAT complexes (6.3±5.9 µg/ml), F1.2 (430.4±202.4 pmol/L), platelet microparticles (13.1±9.3 nM) and protein C levels (90.5±63.4%) with a corresponding decrease in PAI-1 (53.3±18.8ng/ml) and antithrombin levels (80.7±42.4%) compared to normal human plasma were also observed. Biopsy-negative SJS/TEN subjects with less pronounced inflammatory stimulus, demonstrated mild elevation in cytokine levels of IL-4 (1.95±0.59 pg/ml), IL-6 (29.81±25.18 pg/ml), TNF-α (7.20±5.04 pg/ml) and MCP-1 (265.10±159.09 pg/ml)).

Conclusions

T-cell activation and release of cytokines especially TNF-α and granzyme B causes immune-mediated activation of coagulation with increase in TAT, MCP-1, F1.2 and platelet microparticles and corresponding decrease of protein C, antithrombin, and PAI-1. These alterations in coagulation may progress to sepsis associated coagulopathy and overt disseminated intravascular coagulation.

Disclosures:

No relevant conflicts of interest to declare.
Clinical Study Of DC-CIK (dendritic cells and cytokine-induced killer cells ) Eliminate Minimal Residual Leukemia
Authors: Zheng Zhuanzhen , Yuna Zhang , Huimin Zhang , Liu Qingchi , Ma Yanping , Wu Weihai , MA Chuanbao , Pang Yuhui , LI Jianying
Published: October 2019

Objective

To evaluate the clinical efficacy and safety of allogenic dendritic cells (DCs) and cytokine-induced killer (CIK) cells in the eliminating minimal residual leukemia (MRL).

Methods

48 acute leukemia patients with hematological complete remission (CR) but without molecular biological remission (CRM), or patients with minimal residual Leukemia (MRL) were selected from Ping’an Hospital of Shijiazhuang during Jan. 2009 to Jun. 2011. According to the patients’ will, 48 patients divided into combined treatment group and chemotherapy group 24 each. All the patients were in the same general information and disease level. The combined treatment group was treated with DC-CIK and consolidation chemotherapy, and the chemotherapy group was treated with consolidation chemotherapy. PBMCs were collected from healthy donors (the patient's parents or children) to prepare DC-CIK cells. DC-CIK cells were intravenous injected into patients once every 15 days, a total of 4-6 times infusion. The blood routine, bone marrow cells, leukemia related genes, urine and stool routine, liver and kidney biochemistry function, and ECG were observed. Changes of peripheral lymphocyte subsets in patients were detected by flow cytometry. Adverse reactions were examined.

Results

(1)Eleven cases in the combined treatment group achieved CRM, and the CRM rate was 45.8%; whereas only 2 cases in the chemotherapy group achieved CRM and the CRM rate was 8.3%,the difference was statistically significant(χ2=8.55, P<0.01).(2) Compared with the chemotherapy group, the CFIM (four-color combination flow cytometric immunophenotype of minimal residual leukemia) negative conversion rate of patients in the combined treatment group was significantly raised (66.7% vs 25.0%,χ2=8.39, P<0.01). (3)The negative conversion rate of MRL was higher in the combined treatment group than the chemotherapy group (66.7% vs25.0%, χ2=8.39, P<0.01). (4) After treatment the ratio of CD4+/CD8+ cells was significant increased than before treatment in the combined treatment group (1.3±0.4 vs 0.8±0.4, P<0.05). (5)The complete remission rate (CCR) of patients in the combined treatment group after 3 years was 79.2%, while that in the chemotherapy group was 45.8% (χ2=5.69, P<0.05).(6)No dysfunction of critical organs such as heart, liver and kidney and serious adverse reactions were observed while DC-CIK cells infusion.

Conclusion

DC-CIK combined with chemotherapy can inhibit leukemia gene, promote the negative conversion rate of CFIM, facilitate the clear of MRL, improve immune function and prolong remission of the patients.No serious adverse reactions were found in patients with DC-CIK infusion.

Disclosures:

No relevant conflicts of interest to declare.
Puma Is The Critical BH3-Only Protein Mediating Apoptosis In The Nup98-HoxD13 (NHD13) Mouse Model Of Human MDS
Authors: Guirguis Andrew , Curtis David J. , Slape Christopher , Saw Jesslyn , Wei Andrew H , Failla Laura M , Bouillet Philippe , Strasser Andreas
Published: October 2019

One of the key hallmarks of myelodysplastic syndromes (MDS) is that of ineffective haematopoiesis. The main factor contributing to this is increased apoptosis of bone marrow progenitors – a prominent feature particularly of early-stage MDS. Although apoptosis has been attributed to cell extrinsic triggers such as increased levels of Fas and TNF-α, there is increasing evidence implicating the cell intrinsic pathway – in which Bcl-2 and its related proteins play an important role and which is activated by p53. Consistent with this, we have recently shown that apoptosis in the Nup98-HoxD13 (NHD13) transgenic mouse model of MDS can be effectively blocked by enforced expression of Bcl-2. To further define the molecular mechanism of apoptosis upstream of Bcl-2, we mated NHD13 mice with mice deficient for p53. Consistent with a lineage specific role for p53, we observed p53-dependent apoptosis of the erythroid, but not the myeloid lineage. In NHD13 progenitors, gene expression analysis for members of the intrinsic pathway, showed elevated expression of Noxa but not Puma – both of which are BH3-only proteins and transcriptional targets of p53. We proceeded to mate NHD13 mice with mice deficient in Noxa and Puma. Unexpectedly, the expression levels were in fact misleading as genetic ablation studies showed that apoptosis of both erythroid and myeloid lineages was Puma dependent, with no role for Noxa. These studies have demonstrated that gene expression of Bcl-2 proteins cannot be used to predict functional relevance and in this case, Puma is the critical BH3-only protein mediating apoptosis in MDS.

Disclosures:

Guirguis: Leukaemia Foundation - Australia: Research Funding.
Patterns and Outcomes Of First-Line Management Strategies In Older Adults With Low-Grade Follicular Lymphoma (FL)
Authors: Rai Ashish , Nastoupil Loretta J. , Lipscomb Joseph , Ward Kevin , Howard David H. , Flowers Christopher R.
Published: October 2019

Background

Therapeutic decision making for patients with low-grade (grade 1 and 2) FL involves deciding whether to treat, when to treat, and which among the numerous treatment modalities to administer. The lack of trials comparing outcomes of these treatment modalities makes it a complex process. This study seeks to examine the evolving treatment paradigm and evaluate the outcomes of first-line management strategies for low-grade FL in adults aged ≥ 66.

Methods

We used the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database to identify 4,233 low grade FL patients (pts) aged 66 years and older diagnosed between 1995 and 2009. We ascertained first-line management strategies from Medicare claims made within 90 days of diagnosis. We used Kaplan-Meier estimators stratified by stage to evaluate survival functions for first-line management strategies. We used multivariate Cox proportional hazards models—stratified by stage and adjusted for patient demographics, comorbidity index, and year of diagnosis—to compare the impact of first-line management strategies on overall survival (OS).

Results

Of the 4,233 pts, 57% were female, 3% were African American, 93% were White, 51% resided in big metropolitan areas, 70% were diagnosed after 2000, 44% had stage III/IV disease, and 38% had extranodal involvement. The median age at diagnosis was 74 years (interquartile range 70-80). Common first-line management strategies were: observation (obs), 47%; chemotherapy (chemo) plus rituximab (R), 20%; chemo alone, 12%; R alone, 9%; and radiotherapy (XRT) alone, 9%. Among pts receiving chemo plus R (R-chemo), the most commonly used regimens were: R-CHOP (R, cyclophosphamide, doxorubicin, vincristine, and prednisone; 36%), R-CVP (R, cyclophosphamide, vincristine, and prednisone; 47%), R-Fludarabine based (9%), and R-other (7%).

The table displays median survival and hazard ratios (HRs) for first-line management strategies. Among stage I/II cases, most favorable outcomes were observed in cases receiving XRT alone, whereas among stage III/IV cases most favorable outcomes were observed in the group that received R-chemo. In the subset of stage III/IV pts that received R-chemo, R-CHOP was associated with the most favorable outcomes. HRs decreased steadily with increasing years of diagnosis.

Conclusion

First-line R-chemo is commonly used in older adults with low-grade FL in the United States and is associated with most favorable survival outcomes. XRT is associated with very favorable outcomes in stage I/II pts. Outcomes have improved steadily in the past 10 years.

CVP–cyclophosphamide, vincristine, prednisone; CHOP- cyclophosphamide, doxorubicin, vincristine, prednisone

Disclosures:

No relevant conflicts of interest to declare.
Limited Superiority Of Recombinant Thrombomodulin For Disseminated Intravascular Coagulation; A Comparative Analysis In 41 Children
Authors: Nishikawa Eri , Yagasaki Hiroshi , Shimozawa Katsuyoshi , Okuma Hirotsugu , Hirai Maiko , Kato Maiko , Shichino Hiroyuki , Chin Motoaki , Takahashi Shouri , Mugishima Hideo
Published: October 2019

Background and Objectives

Recombinant thrombomodulin (rTM), a new type of natural anticoagulant, has been available in Japan since 2008 for the treatment of disseminated intravascular coagulation (DIC). Since limited information is available on its efficacy in children, we compared the efficacy of rTM to that of conventional treatment.

Patients and Methods

Of 41 children with DIC, 21 were treated with rTM as a first-line therapy (rTM group) and 20 weere treated with conventional treatment (control group). The day on which anti-DIC treatment was first given was defined as day 1. We used the DIC criteria of the Japan Welfare and Health Ministry. We evaluated the overall survival at day 28 after anti-DIC treatment, the cumulative incidence of DIC resolution, and the total fresh frozen plasma (FFP) and platelet transfusion volumes during the course of DIC.

Results

Clinical outcomes are summarized in the Table. Both groups showed comparable overall survival (95.2% in the rTM group and 95.0% in the control group). In addition, the cumulative incidence of DIC resolution in the rTM group (90.5%) was not different from that in the control group (70.0%) (p=0.210) (Figure). However, the median FFP and platelet transfusion volumes in the rTM group (0 U/kg and 0.28 U/kg) were lower those in the control group (0.14 U/kg and 0.76 U/kg) (p=0.041 and 0.063, respectively).

Conclusion

The use of rTM in children with DIC should reduce the social and ethical problems as well as the biological risks associated with human-derived blood products. Although the limited advantages of rTM were shown, the present study was limited by the small and heterogeneous patient population. Therefore, larger prospective studies are warranted to fully evaluate the efficacy of rTM.

Disclosures:

No relevant conflicts of interest to declare.
Passage-Dependent Cancerous Transformation Of Human Mesenchymal Stem Cell Of Adipose Origin During In Vitro Culture
Authors: Kim Jung Ah , Choi Qute , Im Kyong Ok , Kwon Ji Seok , Park Si Nae , Kim Seon Young , Hwang Sang Mee , Oh Yeon-Mok , Lee Dong Soon
Published: October 2019

Introduction

In vitro culture of adult human mesenchymal stem cells (hMSCs) can induce cancerous transformation, depending on environmental factors. To evaluate the passage dependent chromosomal changes of hMSCs toward malignant transformation, we passaged adipose origin hMSC to 9th passage and analyzed cytogenetic change, molecular cytogenetic changes, and telomere length variations on every passage.

Methods

On each passage, in situ karyotyping was performed on 3 separate batches with subsequent Giemsa staining. Karyotyping was analyzed using Metafer system (MetaSystems, Altlussheim, Germany). For analysis of nonproliferating interphase cell, each chromosome were counted with centromere fluorescent in situ hybridization (FISH) using Same Day OligoFISH™(Cellay Inc., Cambridge, Massachusetts, USA). Telomere length was analyzed using FISH technique with a Cy3-lableled Telomere peptide nucleic acid (PNA) FISH kit (DakoCytomation Denmark A/S, Glostrup, Denmark). To confirm the chromosomal translocation appeared by in situ karyotyping, we made home-brew FISH probe with bacterial artificial chromosome(BAC) clone and quantitated the proportion of abnormal cells by interphase FISH.

Results

On 5th passage, translocation and polysomy of chromosome 7 and 9 appeared, and on 6th passage, additional translocation t(6; 10) appeared. ISCN Karyotypes of chromosomal changes from 5th passage to 7th passage were 48,XX,+7,t(7;22)(q11.22;q13.3),+9[4]/46,XX[21] → 47,XX,+7[2]/47,XX,t(6;10)(q21;q25.1),+7[2]/46,XX[13] → 48,XX,+7,t(7;22)(q11.22;q13.3),+9[6]/ 47,XX,+7[5]/46,XX[9]. Telomere length was decreased on late passages. Fusion signal of t(7;22) on passage 5(fig 1) and that of t(6;10) on passage 6(fig 2) were confirmed by BAC clone.

Conclusions

The behavior of late passage (from passage 5) follows a cytogenetic profile similar to that of transformed cancer cells. Cytogenetic abnormalities which were not observed in earlier passage, showed up and disappeared, but eventually persisted during passages. We suggest in vitro environment cause hMSCs to undergo cancer-like cytogenetic changes. It is of great importance to test safeguards for clinical applications of human stem cells manufactured in vitro.

Disclosures:

No relevant conflicts of interest to declare.
Thrombotic Thrombocytopenic Purpura Associated With Hodgkin Lymphoma
Authors: Chao Ju-Hsien , Kloecker Goetz H
Published: October 2019

Introduction

Thrombotic thrombocytopenic purpura (TTP) is characterized by microangiopathic hemolytic anemia and thrombocytopenia with usually less than <5% ADAMTS13 (a disintegrin and metalloprotease with thrombospondin repeats) activity level. Hodgkin lymphoma (HL) comprises 10% of newly diagnosed lymphoma cases.

Case Report

A 45 year old healthy African American male presented with diffuse abdominal pain with associated nausea and constipation. Labs showed decreased hemoglobin, platelets, and haptoglobin with elevated bilirubin, lactate dehydrogenase, and creatinine. ADAMTS13 level was <1%. Peripheral smear revealed schistocytes. CT imaging demonstrated multiple lesions of liver, pleura, and bone, as well as diffuse adenopathy, all later confirmed to be hypermetabolic by PET scan. Pleura biopsy suggested HL. TTP was diagnosed, prompting start of high dose prednisone and plasma exchange (PE). Labs normalized after 5 exchanges, allowing for outpatient steroid and PE tapers. A pleura biopsy was suspicious but not definitive for HL. Three weeks later, he was admitted for opioid-induced constipation. He was still on PE. Despite labs without evidence of TTP, his ADAMTS13 persisted at <1%. A definitive excisional cervical lymph node biopsy yielded classical nodular sclerosing HL. Patient started systemic chemotherapy with doxorubicin, bleomycin, vincblastine, and dacarbazine (ABVD). PE was discontinued 7 days later. At follow-up 3 weeks from cycle #1, ADAMTS13 was 55% without evidence of TTP.

Conclusion

A 2012 review notes 4 cases of microangiopathic hemolytic anemia associated with HL, proposing an underlying immune component to this uncommon entity. Though rare, management of TTP associated HL can be challenging due to underlying cytopenias delaying systemic chemotherapy and yet refractoriness of ADAMTS13 to correct, portending a high risk of TTP relapse, without chemotherapy. Supportive measures to stabilize TTP and prompt initiation of chemotherapy can be an effective approach.

Disclosures:

No relevant conflicts of interest to declare.
Subcutaneous panniculitis-like T-cell lymphoma presented with full facial edema, hemophagocytic syndrome and Epstein-Barr Virus infection:A case report
Authors: Li Lin , Chen Jianyi , Zhang Bing , Zhu Xuejun , Sun Xuemei
Published: October 2019

Background

Subcutaneous panniculitis-like T-cell lymphoma (SPTCL) is a rare and distinct type of T-cell lymphoma. It is frequently associated with hemophagocytic syndrome (HPS), whose etiologic factors always involve Epstein-Barr Virus(EBV) infection. Although EBV is absent in many cases of sporadic SPTCL, we found a case of SPTCL with full facial edema, HPS and EBV infection as the first symptom.

Patient and treatment

A 36-year-old female had presented with fever, full facial edema for 20 days before hospitalization. Remarkable abnormalities were found as hypersplenotrophy, pancytopenia, hypofibrinogenemia, high ferritin and soluble interleukin-2-receptor level, hemophagocytosis in bone marrow smear, which indicated HPS. Detection by PCR of EBV-DNA in peripheral blood was 9.73×104 copies. On the next day of her hospitalization, HLH-2004 protocol (VP-16+dexamethasone+cyclosporine A) was performed. Her temperature fell to normal on the 4th day. Full facial edema vanished gradually in the following days. After 8 weeks’ treatment, all the abnormalities in the laboratory examination returned to normal. Despite of cyclosporine A and prednisone were used as continual treatment, facial edema and fever relapsed accompanied by multiple skin lesions on her back, upper and lower limbs 4 months later. Reexamination of the laboratory index related above were abnormal once again. Copy number of EBV-DNA was 5.52×105. Histologic and immunohistochemical features of tissue biopsy from the skin lesion on her right arm revealed the evidence of SPTCL. Then, she was treated by asparaginase plus DICE regimen. The facial edema and skin lesion vanished gradually during the course of treatment. Now (one month after the first course of chemotherapy), the patient is in her second course of asparaginase plus DICE regimen and SPTCL remains remission.

Conclusion

This was not a typical case of SPTCL. The patient presented with overt skin lesion 4 months after the first symptom of full facial edema, which suggested SPTCL is a heterogenous disease with variable presentations. Awareness of this rare entity is critical to both ensure timely diagnosis and treatment. In addition, the pathogenesis of SPTCL remains unclear. Some malignant lymphomas are induced by chronic inflammation due to viral or bacterial infection. It is well known that EBV infection often causes malignant lymphomas of B-cell type, particularly in elderly peoples and immunocompromised individuals. Although EBV is absent in many cases of sporadic SPTCL, the virus appears to be implicated in the etiology of variant SPTCL occurring in the Asian population.

Disclosures:

No relevant conflicts of interest to declare.
CD44 Monoclonal Antibody-Enhanced Clearance Of Chronic Myeloid Leukemia Stem Cells From The Malignant Niche
Authors: Hellqvist Eva , Holm Frida , Mason Cayla N , Runza Valeria , Weigand Stefan , Sadarangani Anil , Jamieson Catriona H.M.
Published: October 2019

Introduction

Leukemia stem cells (LSC) in chronic myeloid leukemia (CML) are important in disease progression and relapse. Conventional therapy with tyrosine kinase inhibitors (TKIs), although very effective at reducing bulk CML cells, frequently fail to eliminate LSC residing in the protective bone marrow niche. Thus, there is an unmet need for combination therapy that simultaneously targets bulk disease and eliminates LSC in order to prevent disease progression and relapse. Stem cell niches are often rich in hyaluronic acid. CD44, the main receptor for hyaluronic acid, and some of its splice variants are frequently overexpressed on cancer stem cells, including LSC. In this study we aimed to evaluate the in vivo anti-LSC activity of CD44 monoclonal antibody (mAb) RG7356.

Methods and Results

For anti-CD44 LSC inhibition studies, immunodeficient RAG2-/-γc-/- neonatal mice were intrahepatically transplanted with human BC LSC from imatinib responsive and resistant patients. Once engraftment was verified, mice were treated with control IgG1 (30mg/kg/week), dasatinib (25mg/kg/day), CD44 mAb (RG7356) (30mg/kg/week) or a combination of CD44 mAb (RG7356) and dasatinib. The mice were sacrificed after two weeks of therapy and bone marrow, spleen, peripheral blood and myeloid sarcomas were analyzed by FACS to assess CML LSC burden. In the imatinib responsive patient, CD44 mAb single agent therapy showed an 85% reduction of LSC in bone marrow, 98% reduction in spleen and 91% reduction in peripheral blood. CD44 mAb therapy thus showed an efficacy equal to that of dasatinib, which showed an 87%, 98% and 98% reduction in bone marrow, spleen and peripheral blood respectively. Combination therapy (CD44 mAb + dasatinib) completely eradicated any trace of CML LSC in all tissues analyzed. In the imatinib resistant patient, dasatinib very effectively reduced the number of myeloid sarcomas and blasts but did not inhibit LSC survival in bone marrow. In contrast, CD44 mAb single agent therapy effectively reduced the number of CML LSC to 51% in bone marrow, 96% in spleen and 93% in peripheral blood.

Conclusions

This study demonstrates that a human CD44 specific mAb, RG7356, significantly reduces CML LSC survival. Notably, TKI resistance of CML LSC, can be overcome by treatment with a human CD44 specific mAb, RG7356, as it sensitizes CML LSC residing in malignant niches to dasatinib. From these results, RG7356 appears to be an excellent antibody for future combination clinical studies aimed at eradicating CML.

Disclosures:

Runza: employee of Roche Diagnostics GmbH: Employment. Weigand:Roche Diagnostics GmbH: Employment. Jamieson:J&J: Research Funding; Sanofi: Consultancy; Roche: Research Funding.
Causes and Consequences of Cancer-Associated Thrombocytosis
Authors: Sood Anil , Stone Rebecca L. , Afshar-Kharghan Vahid
Published: October 2019

Platelets represent one of the largest storage pools of angiogenic and oncogenic growth factors in the human body. The observation that thrombocytosis (platelet count >450,000/µL) occurs in patients with solid malignancies was made over 100 years ago. However, mechanisms of paraneoplastic thrombocytosis and the role that platelets play in abetting cancer growth are unclear. We have used clinical data coupled with sophisticated mouse models to identify the mechanisms and biological implications of paraneoplastic thrombocytosis. Thrombocytosis was significantly associated with advanced disease and shortened survival. Plasma levels of thrombopoietin and interleukin-6 were significantly elevated in patients who had thrombocytosis as compared with those who did not. In mouse models, increased hepatic thrombopoietin synthesis in response to tumor-derived interleukin-6 was an underlying mechanism of paraneoplastic thrombocytosis. Tumor-derived interleukin-6 and hepatic thrombopoietin were also linked to thrombocytosis in patients. Silencing thrombopoietin and interleukin-6 abrogated thrombocytosis in tumor-bearing mice. Anti-interleukin-6 antibody treatment significantly reduced platelet counts in tumor-bearing mice and in patients with epithelial ovarian cancer. In addition, neutralizing interleukin-6 significantly enhanced the therapeutic efficacy of paclitaxel in mouse models of epithelial ovarian cancer. The use of an anti-platelet antibody to halve platelet counts in tumor-bearing mice significantly reduced tumor growth and angiogenesis. Biologically, platelets were detected within the tumor microenvironment and affected tumor growth and response to chemotherapeutic agents. These findings support the existence of a paracrine circuit wherein increased production of thrombopoietic cytokines in tumor and host tissue leads to paraneoplastic thrombocytosis, which fuels tumor growth. Blocking the stimulatory effects of platelets may have implications for new therapeutic approaches.

Disclosures:

No relevant conflicts of interest to declare.
Molecular Basis of T-Cell Exhaustion
Authors: Wherry E. John
Published: October 2019

T-cell exhaustion is common during chronic infections, cancer, exposure to persisting antigens, and can prevent optimal immunity. Exhausted T cells are defined by the loss of ability to perform effector functions efficiently, low proliferative capacity, and poor survival following antigen stimulation. In addition, it has become clear that exhausted T cells co-express multiple inhibitory receptors that negatively regulate their function. Indeed, receptors such as PD-1 have become major targets of clinical immunotherapies in cancer and infectious disease aimed at re-invigorating exhausted T cells. Our work has recently defined transcriptional networks of T-cell exhaustion and has focused on the role of key transcription factors, including T-bet and Eomesodermin (Eomes), in controlling the sustainability and terminal differentiation of exhausted T cell populations. Chronic infections and persisting antigen exposure often strains the sustainability or regenerative capacity of exhausted T cell populations resulting in an eventual collapse in immunity. We have found a key role for T-bet in sustaining a progenitor pool of exhausted CD8 T cells during chronic infection, while the related transcription factor Eomes governs terminal differentiation. These represent unique functions for T-bet and Eomes since these transcription factors are associated with different roles in functional memory T cells, highlighting the contextual dependence of transcriptional regulation guiding T-cell exhaustion. Additional studies are focusing on the role of other transcription factors such as BATF in T-cell activation and exhaustion, and on the role of inhibitory receptors including PD-1 in shaping the differentiation of exhausted CD8 T-cell subsets. Ultimately, a more precise molecular understanding of T-cell exhaustion should lead to novel and more robust clinical interventions to reverse exhaustion in settings of persisting infections and cancer.

Disclosures:

Wherry: Genentech: Patents & Royalties.
Bortezomib-Containing Regimens for Multiple Myeloma Maintenance Therapy: a Meta-Analysis
Authors: Wang Yucai , Zhang Wenwen , Yang Fang , Guan Xiaoxiang , Kothari Neil , Chang Victor , Wang Michael
Published: October 2019

Objective: To evaluate the efﬁcacy and safety of bortezomib-containing regimens in maintenance therapy of multiple myeloma through meta-analysis of randomized controlled trials (RCTs).

Patients and methods: PubMed, Web of Science and ASH databases were searched for RCTs that investigated the treatment outcomes (progression-free survival [PFS] and overall survival [OS]) of maintenance therapy with bortezomib-containing regimens in patients with multiple myeloma. Study endpoints included PFS, OS, and grade 3 or 4 adverse events. Pooled hazard ratios (HRs) for survival outcomes and risk ratios (RRs) for dichotomous data with 95% confidence interval (CI) were calculated using Comprehensive MetaAnalysis (v2).

Results: Three RCTs comprising 1396 patients were included in this meta-analysis. Compared with maintenance therapy without bortezomib and/or no maintenance therapy, bortezomib-based maintenance therapy regimens significantly prolonged PFS (HR = 0.66, 95% CI = 0.58 - 0.76, P < 0.001) and OS (HR = 0.74, 95% CI = 0.62 - 0.88, P = 0.001) in multiple myeloma patients. In patients who received high-dose chemotherapy followed by autologous stem cell transplantation (ASCT), bortezomib-based maintenance therapy increased both PFS (HR = 0.73, 95% CI = 0.61 - 0.86, P < 0.001) and OS (HR = 0.76, 95% CI = 0.61 - 0.95, P = 0.016). For transplant ineligible patients, maintenance therapy with bortezomib-containing regimen also increased PFS (HR = 0.58, 95% CI = 0.47 - 0.71, P < 0.001) and OS (HR = 0.70, 95% CI = 0.52 - 0.92, P = 0.012). However, bortezomib-based maintenance therapy increased the risks of grade 3 or 4 adverse events including thrombocytopenia (RR = 1.37, 95% CI = 1.01 - 1.87, P = 0.046), infections (RR = 1.29, 95% CI = 1.02 - 1.64, P = 0.035), cardiac disorders (RR = 2.01, 95% CI = 1.17 - 3.47, P = 0.012), and vascular events (RR = 2.02, 95% CI = 1.15 - 1.45, P= 0.015).

Conclusions: Bortezomib-based maintenance therapy results in signiﬁcant improvement in PFS and OS in multiple myeloma patients, but may increase the risk of developing some grade 3 or 4 adverse events, such as thrombocytopenia, infections, cardiac disorders, and vascular events. Further studies are needed to corroborate the above findings given the limited data on proteasome inhibitor based maintenance therapy for multiple myeloma.

Disclosures

No relevant conflicts of interest to declare.
Calr Is up-Regulated in Patients with Essential Thrombocythemia Independently from Calr and JAK2 Mutations
Authors: Brown Lilia , Graham Ciaren , Rinaldi Ciro
Published: October 2019

Somatic mutations in exon 9 of calreticulin (CALR) gene were recently discovered in patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF) lacking JAK2 and MPL mutations, and absent in patient with polycythemia vera (PV). Among patients with ET or PMF with un-mutated JAK2 or MPL, CALR mutations were detected in 67% of those with ET and 88% of those with primary PMF. Several types of insertions or deletions were identified and all resulted in a frameshift in exon 9 generating a novel C-terminal peptide in the mutant CALR protein. Over expression of the most frequent CALR deletion caused cytokine-independent growth in vitro owing to the activation of signal transducer and activator of transcription 5 (STAT5) by means of an unknown mechanism. Patients with myeloproliferative neoplasms carrying CALR mutations present with higher platelet counts and lower haemoglobin levels than patients with mutated JAK2. Studies suggest these patients have a lower risk of thrombosis and longer overall survival than patients with mutated JAK2.

We analysed by Real Time PCR, CALR expression in peripheral blood (PB) of 38 patients affected by ET, 17 JAK2 mutated (45%), 4 CALR (10.5%) mutated, 1 MPL mutated (3%) and 14 with no apparent molecular abnormalities. These were compared with a cohort of healthy volunteers. We found a significant over expression of CALR (median 5.15; range 1.13-270.08) comparing with controls (median 0.38, range 0.18-1). CALR mRNA expression is independent from the CALR mutational status. No significant difference was found comparing CALR expression in CALR mutated (median 4.9, range 1.51-37.14) and CALR/JAK2 un-mutated patients (4.68, range 1.51-28.71). CALR up-regulation is not mutually exclusive with JAK2 mutations; no difference was seen in CALR mRNA between JAK2 mutated (median 5.09, range 1.13-270) and wild type ET patients (median 5.08, range 1.51-37). There was no significant difference when we correlated CALR expression with PLT counts, spleen size or type of cytoreductive therapy. A larger cohort of patients is required to confirm these preliminary findings.

Disclosures

No relevant conflicts of interest to declare.
Mutually Exclusive Recurrent Somatic Mutations in MAP2K1 and BRAF Support a Central Role for ERK Activation in LCH Pathogenesis
Authors: Chakraborty Rikhia
Published: October 2019

Langerhans Cell Histiocytosis (LCH) is a myeloproliferative disorder characterized by lesions composed of pathologic CD207+ dendritic cells (DCs) with an inflammatory infiltrate. BRAFV600E remains the only recurrent mutation reported in LCH. In order to evaluate the spectrum of somatic mutations in LCH, whole exome sequencing (WES) was performed on matched LCH and normal tissue samples obtained from 41 patients. Lesions from other histiocytic disorders, juvenile xanthogranuloma (JXG), Erdheim-Chester disease (ECD), and Rosai-Dorfman disease (RDD) were also evaluated. All of the lesions from histiocytic disorders were characterized by an extremely low overall rate of somatic mutations. Notably, 33% (7/21) of LCH cases with wild-type BRAF and none (0/20) with BRAFV600E harbored somatic mutations in MAP2K1 (six in-frame deletions and one missense mutation) that induced ERK phosphorylation in vitro. Single cases of somatic mutations of the MAPK pathway genes ARAF and ERBB3 were also detected. The ability of MAPK pathway inhibitors to suppress MEK and ERK phosphorylation in cell culture and primary tumor models was dependent on the specific LCH mutation. The findings of this study support a model in which ERK activation is a universal endpoint in LCH arising from pathologic activation of upstream signaling proteins.

Disclosures

No relevant conflicts of interest to declare.
Angiogenesis Associated with Alterations of the Bone Marrow Microenvironment Predicts Multiple Myeloma Progression to Symptomatic Disease in Mice and Humans
Authors: Calcinotto Arianna , Ponzoni Maurilio , Ria Roberto , Grioni Matteo , Cattaneo Elena , Villa Isabella , Bertilaccio Maria Teresa Sabrina , Chesi Marta , Rubinacci Alessandro , Tonon Giovanni , Bergsagel Peter Leif , Vacca Angelo , Bellone Matteo
Published: October 2019

While multiple myeloma (MM) is almost invariably preceded by asymptomatic monoclonal gammopathy of undetermined significance (MGUS) and/or smoldering MM (SMM), the alterations of the bone marrow (BM) microenvironment that establish progression to symptomatic disease are circumstantial. Our aim was to identify changes in the BM microenvironment eliciting angiogenesis in MM.

We have found that in Vk*MYC mice harboring oncogene-driven plasma cell proliferative disorder, the progression from asymptomatic to symptomatic MM was characterized by substantial modifications of the BM microenvironment, including a switch from a T helper type 1 (Th1) to a Th2 response, and accumulation of CD206+Tie2+ macrophages, which eventually favored angiogenesis and increased in microvessel density (MVD). Notably, MVD was also increased at diagnosis in the BM of MGUS and SMM patients that subsequently progressed to MM when compared with MGUS and SMM that remained quiescent.

These findings suggest a multistep pathogenic process in MM, in which the immune system may contribute to angiogenesis and disease progression. They also suggest investigating MVD in asymptomatic patients as prognostic factor for the progression and outcome of this disease.

Disclosures

No relevant conflicts of interest to declare.
Synergistic in Vitro Activity of MOR202, a Human CD38 Antibody, in Combination with Pomalidomide
Authors: Endell Jan , Boxhammer Rainer , Steidl Stefan
Published: October 2019

Background: MOR202 is a fully human anti-CD38 antibody currently being tested in a Phase I/IIa clinical trial in multiple myeloma (MM). It mediates antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) in MM cells with high potency (EC50 ~200 pM) representing a possible promising new therapy for MM patients. In this in vitro study, we evaluated the synergistic potential of MOR202 and pomalidomide (POM), a newly approved IMiD® immunomodulatory agent in MM therapy.

Methods: Using flow cytometry analysis, POM was evaluated in relation to its effects on several parameters anticipated to be relevant for anti-tumor activity when combined with MOR202. This included the induction of direct cytotoxicity and CD38 upregulation in several MM cell lines, as well as the activation of human immune effector cells derived from peripheral blood mononuclear cells of healthy donors. On a functional level the interaction of MOR202 and POM was assessed using FACS-based ADCC assays. Different incubation schemes prior to the ADCC assays were evaluated in order to distinguish the influence of POM on ADCC activity when pre-incubated for 72 hours either on target or effector cells or on both in parallel. The observed combination effects were analyzed for synergistic potential. Experiments were carried out in triplicate and mean values (±SEM) were calculated.

Results: POM as a single agent showed cytotoxic effects on MM cell lines with high potency (EC50 ~150 nM) and additionally induced an up to 2.7-fold upregulation of CD38 (EC50 ~20 nM) on CD38-expressing MM cell lines. Both effects were maximal at the last tested time point of 72 hours and strongest on cell lines with comparably lower CD38 expression levels. In combination with the observed activation of effector cells these POM-mediated mechanisms lead to a synergistically enhanced cytotoxic activity of MOR202. This synergistic benefit ranged between 1.2-fold and 3.1-fold above theoretical additivity depending on the cell line used and was most pronounced in the case of strong CD38 upregulation.

Figure 1 Exemplary ADCC dose-response curves for the comparably lower CD38 expressing cell line AMO-1 after POM pre-treatment of effector cells, target cells or both. Figure 1. Exemplary ADCC dose-response curves for the comparably lower CD38 expressing cell line AMO-1 after POM pre-treatment of effector cells, target cells or both.

Conclusions: The cytotoxic activity of MOR202 on MM cells was enhanced and synergized when combined with the immunomodulator agent POM via multiple mechanisms, namely direct cytotoxicity, CD38 upregulation and activation of effector cells. These results provide a mechanistic rationale for combining MOR202 and POM and warrant further evaluation in the clinical setting.

Disclosures

Endell: MorphoSys AG: Employment, Patents & Royalties. Boxhammer:Morphosys AG: Employment, Patents & Royalties. Steidl:MorphoSys AG: Employment, Patents & Royalties.
Evaluation of the Bacterial Etiologies of Infections in Patients Undergoing Hematopoietic Stem Cell Transplantation
Authors: Hizmali Lokman , Tapan Umit , Eraksoy Haluk
Published: October 2019

Objectives: Bacterial infections increase morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). The characteristics of the bacteria causing infections in these patients undergo dynamic changes both globally and locally during the transplantation process. The etiology of bacterial isolates and analysis of changes in the antibiotic sensitivities are crucial for the selection of appropriate prophylactic and empiric therapies. In this study we aimed to evaluate the first episode of bacterial infection in patients undergoing allogeneic or autologous hematopoietic stem cell transplantation and to identify bacterial isolates and the resistance profile of causative bacteria.

Materials and Methods: In this retrospective study, the charts of 195 patients who underwent allogeneic or autologous hematopoietic stem cell transplantation between January 2010 and December 2013 were reviewed. Ninety-six patients who had microbiologic evidence of bacterial infection were included in the study. The culture results from the first infectious episode during the transplantation process were evaluated. Patients were grouped according to the type of transplantation, and categorized according to the transplantation process, presence of neutropenia and infection status. Microbiological examination of samples obtained for culture and sensitivity analysis were performed according to standards of the National Committee for Clinical Laboratory Standards Institute (CLSI).

Results: Gram-negative and Gram-positive bacteria were identified in 54.2% and 44.8% of the infectious episodes, respectively. Poly-microbial etiology was identified in only 1.0% of these episodes. E. coli and coagulase-negative staphylococci (CoNS) were the most frequently isolated pathogens. In the early stage infections, Gram-positive organisms were more frequently isolated (72.1%) (p=0.042) and a significantly larger number of patients had undergone autologous stem cell transplantation (p<0.001). This situation was explained by the absence of antimicrobial prophylaxis in the autologous group, intensive induction chemotherapy, presence of catheter and mucosal damage. The frequency of extended-spectrum β-lactamase (ESBL) was found to be very high in the allogeneic group compared to the autologous group (36.4% vs. 13.3%). All of the staphylococcal isolates in the allogeneic group were noted to be methicillin resistant.

Conclusions: Treatment and prophylaxis have become increasingly more challenging with the infections caused by resistant pathogens. It is imperative to carefully monitor causative agents of bacterial infections and to plan prophylactic and empiric treatments according to characteristics of the individual patients.

Disclosures

No relevant conflicts of interest to declare.
Defibrotide for Prophylaxis of Hepatic Veno-Occlusive Disease in Autologous, Non-Purged Peripheral Stem Cell Transplantation for High Risk Neuroblastoma Patients
Authors: Unal Emel , Tacyildiz Nurdan , Yavuz Gulsan , Dincaslan Handan , Tanyildiz Gulsah , Ayyildiz Erol , Ozcan Muhit
Published: October 2019

High-dose chemotherapy (HDC) represents the standard of treatment for high-risk neuroblastoma(NBL), hepatic veno-occlusive disease (VOD) is a common, 10-50% and serious complication of haematological stem cell transplantation (HSCT), with up to 90% mortality rates. We planned study to assess whether the use of prophylactic defibrotide in paediatric patients who were heavily treated with chemo-radiotherapy before transplant, and then underwent autologous HSCT.

Seventeen patients who underwent autologous, unpurged peripheral stem cell transplantation PBSC with a high risk of developing VOD, between January 2003-July 2014, were given Defibrotide prophylaxis 25mg/kg/day for 30 days, commencing on -1 of conditioning regimen. All patients were stratified by INSS stage, age, N-MYC status. All were treated with six cycles of induction chemotherapy, myeloablative intensification, surgery for primary site, radiation therapy to the primary tumour site plus metastatic sites i.e bone metastases including skull. Meta-iodobenzylguanidin treatment as targeted radiotherapy was given on -21 prior to myeloablative chemotherapy. Oral 13-cis retinoic acid was employed on day +90 post-transplant. CD34+ cell mobilization and PBSC collection was carreid out after two-four cycles of induction cycles. Conditioning regimen and stem cell infusion was done following four-six weeks of last chemotherapy cycle, in order to reduce the toxicitiy. Conditioning regimen CEM consisted Carboplatin, Etoposide, Melfalan. There were no toxic deaths. All of the patients receieved antimicrobial prophylaxis and total parenteral nutrition support when was needed. Myeloid engraftment on day+13, erythroid engraftment on day+18 and thrombocyte engraftment was achieved on day +23.

Defibrotide prophylaxis seems to reduce incidence of VOD and is well tolerated. VOD incidence and severity was reduced in the defibrotide group which suggests that defibrotide might be effective in preventing and treating VOD. Sufficiently powered randomised trials are now required to definitively test the role of defibrotide in this setting.

Disclosures

No relevant conflicts of interest to declare.