bluuebunny/crossref_metadata_2025 huggingface dataset:
Pharmacological Inhibition of Fatty Acid Oxidation as a Novel Therapeutic Concept for Acute Myeloid Leukemia.
Authors: Andreeff Michael , Fiegl Michael , Konopleva Marina , Korchin Borys , Kaluarachchi Kumar , Bornmann William G. , Guthrie Patrick H. , Harmancey Romain , Taegtmeyer Heinrich , Samudio Ismael J.
Published: October 2019

Abstract 3779

Poster Board III-715

Otto Warburg proposed that the origin of cancer cells was closely linked to a permanent respiratory defect that bypassed the Pasteur effect, i.e. the inhibition of anaerobic fermentation by oxygen. We have recently demonstrated in leukemia cells that mitochondrial uncoupling, i.e. the abrogation of ATP synthesis in response to mitochondrial membrane potential (MMP), promotes the Warburg effect, contributes to chemo-resistance and represents a metabolic shift to fatty acid oxidation (FAO). Exposure of leukemic cells to marrow-derived mesenchymal stromal cells (MSC) promotes accumulation of lactate and reduces MMP. Stroma/leukemia co-cultures protect leukemia cells from chemotherapy-induced apoptosis. We found that he decrease in MMP was mediated by mitochondrial uncoupling accompanied by increased expression of mitochondrial uncoupling protein (UCP2) (Cancer Res. 68:5198,2008). We therefore proposed that the Warburg effect may be the result of preferential oxidation of fatty acids in cancer cell mitochondria (Cancer Res.69:2163,2009). Here we demonstrate that leukemia cells uncouple FAO from ATP synthesis, and that pharmacological inhibition of FAO with etomoxir or ranolazine inhibits proliferation and sensitizes leukemia cells – cultured alone or on bone marrow stromal cells – to apoptosis induction by the BH3 mimetic ABT-737 and the MDM-2 antagonist Nutlin 3a. Results suggest that leukemia cells rely, at least in part, on de novo fatty acid synthesis (FAS) to support FAO. Furthermore, treatment with the FAS inhibitor orlistat sensitized leukemia cells to apoptosis induction by ABT-737. Mechanistically, mitochondria derived from etomoxir treated leukemia cells were sensitized to release of cytochrome C and apoptosis-inducing-factor (AIF) upon treatment with ABT-737. Etomoxir (EX) facilitated the formation of Bak oligomers after treatment with ABT-737 suggesting that FAO regulates the activity of Bak-dependent mitochondrial permeability transition. Lastly, we present evidence that EX, in combination with liposomal ABT-737 or cytosine arabinoside (AraC), provides significant therapeutic benefit in a murine model of human leukemia (luciferase/GFP marked MOLT13 cells) as evidenced by reduced in vivo growth kinetics (BLI) and prolonged median survival (ABT-737 vs. EX+ABT-737, p=<0.05; AraC vs.EX+AraC,p<0.0001 ). Conclusions: 1) results support the notion that the Warburg effect may be the result of preferential oxidation of fatty acids by leukemia mitochondria. 2) Inhibition of fatty acid oxidation is proposed as a novel therapeutic concept for hematological malignancies.

Disclosures:

No relevant conflicts of interest to declare.
Engineering VSV-IFN-NIS for the Treatment of Multiple Myeloma.
Authors: Naik Shruthi , Nace Rebecca A. , Hadac Elizabeth A. , Dingli David , Federspiel Mark , Barber Glen N. , Russell Stephen J.
Published: October 2019

Abstract 378

The need for new and more effective long-term treatments for Multiple Myeloma (MM) has led to the utilization and engineering of replication competent (oncolytic) viruses as potential therapies. Vesicular stomatitis virus (VSV) is a potent oncolytic agent with several features that make it a favorable choice as a potential myeloma therapy. Specifically, (i) VSV replicates rapidly and can be grown to high titers (for effective clinical use) (ii) VSV undergoes transcription and replication exclusively in the cytoplasm avoiding host genome integration (iii) there is low/absent pre-existing immunity against VSV among the general population, (iv) naturally occurring human VSV infections are generally asymptomatic or result in minimal flu-like symptoms, (v) VSV is not easily transmitted between individuals (natural transmission is by hematophagous insects). Previously we showed weak oncolytic efficacy with an attenuated strain of VSV coding for the sodium iodide symporter (NIS) gene, VSV-D51-NIS, in the immune competent 5TGM1 syngeneic MM mouse model (C57Bl/KalwRijHsd) (Goel at. al. Blood. 2007 Oct 1;110(7):2342-50). Since VSV replication is strongly inhibited by IFN-induced innate immune responses in normal cells, but not in myeloma cells and IFN has known anti-myeloma activity, we hypothesized that the IFN-coding VSVs would be safer and more potent than previously tested VSV recombinants. We therefore constructed and tested the efficacy of VSVs coding for b-Interferon (VSV-IFN) or b-IFN and NIS (VSV-IFN-NIS). Interestingly, all of the newly constructed viruses, including VSV-IFN-NIS, showed greatly superior replication kinetics compared to the previously reported VSV-D51-NIS virus. Furthermore, compared to VSV-D51-NIS, VSV-IFN-NIS vectors induced higher NIS expression in vitro. In vivo therapy studies showed that a single intravenous dose of each of the IFN-coding VSVs promoted tumor regression and significantly prolonged survival of immunocompetent mice bearing subcutaneous or orthotopic 5TGM1 myeloma tumors. Tc-99m imaging studies conducted in mice treated with VSV-IFN-NIS, showed tumor specific virus mediated NIS expression and radio-isotope uptake that increased concurrently with intratumoral viral spread. Most importantly, there was no evidence of neurotoxicity following treatment with the IFN-coding VSVs. These studies indicate that VSV-IFN-NIS has potential as a novel therapeutic agent for multiple myeloma that can be combined with radio-isotopes for both non-invasive imaging of viral biodistribution and radiovirotherapy. A phase I clinical study is currently planned.

Disclosures:

No relevant conflicts of interest to declare.
Azacitidine Is Effective in Patients with Low / Intermediate-1 Risk Myelodysplastic Syndrome Managed in Community Based Practice: Preliminary Data From the Spanish Compassionate Use Registry.
Authors: Garcia Regina , de Miguel Dunia , Bernal Maria-Teresa , Tormo Mar , Sanz Guillermo , de Paz Raquel , Figueredo Antonio , Amutio Maria E , Guzmán José L.
Published: October 2019

Abstract 3801

Poster Board III-737

Background

Myelodysplastic syndrome (MDS) is comprised of a group of heterogeneous hematological disorders. Although the decision regarding treatment of a patient with MDS is based on performance status, age, patient preference and concomitant illnesses, NCCN-recommended treatment approaches vary according to IPSS risk score. Azacitidine (AZA) is a hypomethylating agent recently approved in Europe for the treatment of MDS. AZA was available in Spain under compassionate use before its regulatory approval and marketing authorization from the Spanish Medicines Agency in May 2009.

Material and Methods

We present the preliminary analysis of the clinical data from a longitudinal, multicenter Spanish patient registry. Data on the disease course and management of patients with MDS treated with AZA under compassionate use conditions were retrospectively collected from community-based hematology clinics. As of August 1, 2009, data from 90 patients MDS diagnosed according to WHO criteria had been collected with low / intermediate-1 International Prognostic Scoring System (IPSS) risk score.

Results

At baseline, the median age was 70 years, the male/female ratio was 69/31, and the majority of patients had primary MDS (80 patients; 90%) and an ECOG performance status of 0-1 (62 patients; 69%). The most frequent initial dose of AZA administered was 75 mg/m2 (77 patients, 86%). Almost all patients followed one of the following three schedules: days 1-7 (31%), days 1-5 and 8-9 (29%) or days 1-5 (37%) in a 28-day cycle. AZA was administered mostly subcutaneously (71 patients, 79%). The mean number of cycles administered was 7 (range 2-25). The overall treatment response was 61% (International Working Group 2006 criteria): 21% complete response, 11% complete bone marrow response, 3% partial response, 27% hematological response. In addition, 12% had stable disease. AZA was generally well tolerated. Grade 3/4 adverse events documented in these patients, regardless of their relationship to the active treatment, were neutropenia (48%), thrombocytopenia (36%), anemia (26%), febrile neutropenia (12%), rash (3%), injection site reaction (2%), asthenia (1%), septic shock (1%), constitutional symptoms (1%), and hypotension (1%).

Conclusion

These preliminary results demonstrate that, in a community-based setting, patients with low / intermediate-1 IPSS risk MDS respond to treatment with AZA, with an acceptable safety profile. More data derived from this registry and from the clinical trials are awaited.

Disclosures:

No relevant conflicts of interest to declare.
Efficacy of ICT with Deferasirox in Transfusional Iron Overloaded Patients with MDS or AA.
Authors: Cheong June-Won , Kim Hyeoung-Joon , Lee Kyoo-Hyung , Yoon Sung-Soo , Lee Jae Hoon , Park Hee-Sook , Kim Jin Seok , Kim Ho Young , Shim Hyeok , Seung Chu-Myung , Kim Chul Soo , Chung Jooseop , Hyun Myung Soo , Jo Deog-Yeon , Jung Chul Won , Sohn Sang Kyun , Yoon Hwi-Joong , Kim Byung Soo , Joo Young-Don , Park Chi-Young , Min Yoo-Hong
Published: October 2019

Abstract 3810

Poster Board III-746

PURPOSE

Transfusion-related iron overload and its consequences are emerging challenges in chronically transfused patients with myelodysplastic syndromes (MDS) or aplastic anemia (AA). The clinical data on specific benefits of deferasirox in transfusion-related iron overload patients with MDS or AA has been limited. METHODS: We have prospectively investigated the efficacy of deferasirox by serial measurement of s-ferritin level and LIC by R2-MRI in transfusional iron overload patients with MDS or AA. RESULTS: A total of 79 patients with de novo MDS (n = 29) or idiopathic AA (n = 50) showing serum ferritin level over 1,000ng/ml were enrolled from 23 institutes. Mean value of s-ferritin level in enrolled patients was 4,788 ng/ml in MDS and 4,188 ng/ml in AA at the time of deferasirox initiation. Mean value of LIC was 24.4 mg Fe/g dry weight in MDS and 22.4 mg Fe/g dry weight in AA. Deferasirox was given orally at a dose of 20 mg/kg/day for at least 6 months to all patients and was withheld If the s-ferritin falls below 500 ng/ml. Over the study period, patients with MDS or AA received a mean of 3.7 and 2.7 units RBC per month, respectively. After 12 months of medication, s-ferritin level significantly decreased by 1824.0 ng/ml form baseline values, a reduction of 38.1% for patients with MDS (p<0.0001) and significantly decreased by 3559.1 ng/ml (85.0%) for patients with AA (p<0.0001). LIC decreased by 11.2 mg Fe/g dry weight, a reduction of 35.7% for patients with MDS, and significantly decreased by 8.1 mg Fe/g dry weight, a reduction of 27.6% for patients with AA (p=0.0028). The patients with lower transfusional requirements (<4 units/month) during the study showed significantly more reduction of LIC level than those with higher requirements (≥4 units/month) (35.7% vs. 2.8%; p<0.0001). The most common drug-related adverse events (AE) were gastrointestinal disturbances and non-progressive increase in s-creatinine, however, AE were transient and mild-to-moderate in severity. All death was ascribed to disease-related causes including cytopenia in nine (11.4%) and disease progression in one (1.3%). CONCLUSION: Deferasirox is effective in reducing LIC and s-ferritin level in transfusional iron overload patients with MDS or AA, even with ongoing transfusion requirement, and well tolerated.

Disclosures:

No relevant conflicts of interest to declare.
Initial Evaluation of a 48-h Continuous Intravenous Infusion Weekly Regimen of ON 01910.Na in Advanced Myelodysplastic Syndrome (MDS).
Authors: Raza Azra , Galili Naomi , Ali Muhammad Shahzad , Ali Fahad , Goodman Alyssa , Qasim Samir Ahmed , Wilhelm Francois
Published: October 2019

Abstract 3815

Poster Board III-751

Following initial promising clinical results reported at ASH 2008 (Shenoy et al) in RAEB MDS and AML patients treated with the new investigational agent ON 01910.Na, we have initiated a phase 1/2 single arm escalating dose study in advanced MDS patients with a shorter schedule of administration of ON 01910.Na. The first 13 patients enrolled in our ongoing trial (6 high risk, 1 Intermediate-2 and 5 Intermediate-1 according to IPSS classification; 7 females/6 males, age range: 47-83ys), most of them having failed prior MDS therapies were administered ON 01910.Na as a 48 h continuous intravenous infusion weekly for 3 weeks of a 4-week cycle. Ten patients were treated at the 800 mg/m2/day dose level and 3 at the 1500 mg/m2/day dose level for 4 to 27+ weeks (1 to 6 four-week cycles). Most patients had grade 3 or 4 cytopenias at baseline. Overall the therapy was well tolerated and a few patients reported improvements of well being and pain relief. The most frequently reported adverse events were thrombocytopenia, neutropenia, anemia, fatigue and nausea. Serious adverse events were typical of this patient population and none of them was related to ON 01910.Na except for one case of neutropenia. Bone marrow blastic response was evaluated by bone marrow morphology. Five patients had a pretreatment blast count lower than 5% and no worsening of blast count was observed in the 3 patients who had follow-up bone marrow examination. Another six patients had more than 5% pretreatment bone marrow blasts. Among these patients, two had significant decreases in blast counts compared to pre-treatment values, while two showed stabilization and two progressed. Two patients had hematological improvements (neutrophil and erythroid responses). These results are encouraging and the trial is continuing.

Patient Bone Marrow Blasts Hematological Improvement Pre-Treatment 4-8 week Follow-up 1 <2% 2% 2 10-13% Death end 1st cycle 3 1-2% Not Done (Platelet =4) 4 20-30% 30% N wk 10-18 5 <5% 3% 6 3% Death end 2nd cycle 7 <5% 1-2% 8 25% 11% 9 10-13% 15%* E wk 1-13 10 35% Discontinued mid 2nd cycle (transplant) 11 9% 5% 12 10% 2% 13 15% 20% * 16 week Follow-up: 25% blasts

Disclosures:

Wilhelm: Onconova: Employment.
Lenalidomide Modulates the Phenotype and Function of Human Mesenchymal Stromal Cells From Healthy Donors and MDS Patients.
Authors: Wobus Manja , Dünnebier Gwendolin , Feldmann Silvia , Ehninger Gerhard , Bornhauser Martin , Platzbecker Uwe
Published: October 2019

Abstract 3816

Poster Board III-752

Introduction

Recent studies in patients with MDS have clearly demonstrated the clinical efficacy of lenalidomide. However, its exact mechanisms of action have not been elucidated yet. Myelosuppression is the most common adverse event and seems to be dependent on dose as well MDS subtype, being rather infrequent in patients other than del5q. The aim of this study was to investigate whether lenalidomide affects the bone marrow microenvironment. Therefore, we analyzed in-vitro characteristics of isolated mesenchymal stromal cells (MSCs) from MDS patients and from healthy controls.

Methods

Bone marrow samples were collected from healthy donors (n=5) and patients with MDS (del5q MDS n=3, RA n=2, RAEB1/2 n=3). MSCs were isolated according to the standard adhesion protocol and cultured in the presence or absence of lenalidomide.

Results

Lenalidomide treatment of MSCs caused no morphological changes but proliferation was slightly increased. Typical surface molecules as CD73, CD90, CD105 and CD166 were expressed in MSCs from MDS patients at comparable levels to healthy controls. Lenalidomide treatment caused an upregulation of CD29 by 17.8 ± 4.4% and of CD73 by 24 ± 5.7% (mean fluorescence intensity). Investigating the cytokine production, we found lower IL-8 mRNA and protein levels in MSCs from MDS patients (mean in MDS MSC: 138.1 pg/ml vs. mean in healthy MSC: 1177 pg/ml). Interestingly, the IL-8 production can be increased by approximately 40% under lenalidomide treatment. MDS MSCs retained the capacity for adipogenic and osteogenic differentiation as well as their supportive function towards hematopoietic cells in long term culture-initiating assays (LTC-IC). However, the LTC-IC frequency was lower on MSC which had been preincubated with lenalidomide compared to controls. Lenalidomide also slightly accelerated osteogenic differentiation because mineralization started as early as on day 5 with lenalidomide whereas in the control cells first calcium deposits were visible after 7 days. Other samples showed augmented lipid vacuoles after adipogenic differentiation under lenalidomide treatment.

Conclusion

In conclusion, lenalidomide modulates the phenotype of MSC and leads to an increase of their IL-8 secretion by a yet unknown mechanism. Whether these in-vitro effects are associated with the clinical efficacy of this compound in patients with MDS remains to be investigated.

Disclosures:

Platzbecker: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.
FcRL5 as a Target of Antibody-Drug Conjugates for the Treatment of Multiple Myeloma.
Authors: Polson Andrew G. , Zheng Bing , Elkins Kristi , Lau Jeffery , Go Mary Ann T. , Scales Suzie J. , Yu Shang-Fan , Chesi Marta , Bergsagel P. Leif , Ebens Allen J.
Published: October 2019

Abstract 3836

Poster Board III-772

Antibody-drug conjugates (ADCs), potent cytotoxic drugs linked to antibodies via specialized chemical linkers, provide a means to increase the effectiveness of chemotherapy by targeting the drug to neoplastic cells while reducing side effects. Target selection is a key component to the success of an ADC. In addition to expression on the tumor, the target should have limited expression on normal tissues. The most prevalent and best-studied surface antigens on multiple myeloma (MM) cells, CD138, CD38, CD72, and CD56, all have relatively broad expression patterns that may lead to target-dependent toxicities with ADCs. We have previously shown that FcRL5/FcRH5/IRTA2 is expressed only on B-cells and plasma cells. Here we show that FcRL5 is expressed on the surface of MM cells from 85% of patients and thus could be a target for antibody and ADC treatments of MM. As experience in humans with anti-CD20 antibodies suggests that depletion of B-cells does not present a major safety issue, FcRL5 appears to have an excellent expression pattern as an ADC target for MM. Internalization of target antigens is known to increase the efficacy of ADCs and we found that FcRL5 is internalized upon antibody binding, an ideal trait. We made two different ADCs consisting of anti-FcRL5 antibodies 1) conjugated through cysteines to monomethylauristatin E (MMAE) by a maleimidocaproyl-valine-citrulline-p-aminobenzyloxycarbonyl (MC-vcPAB) linker that is designed to be cleaved by cathepsins (Anti-FcRL5-MC-vcPAB-MMAE); and 2) conjugated via lysines to the maytansinoid DM4 through a disulified linker designed to be cleaved by reducing conditions (anti-FcRL5-SPDB-DM4). These ADCs were tested for cell killing in vitro and in xenograft studies using OPM2 cells stably expressing FcRL5. While unconjugated anti-FcRH5 and control ADCs were not effective, anti-FcRL5-MC-vcPAB-MMAE and anti-FcRL5-SPDB-DM4 were effective at killing this MM cell line both in vitro and in vivo. Furthermore, the anti-FcRL5-SPDB-DM4 conjugate was effective in a SCID-rabbit bone model of MM using the LD cell line. These data suggest that FcRL5 ADCs could be an effective treatment for MM.

Disclosures:

Polson: Genentech, Inc.: Employment, Equity Ownership. Zheng:Genentech, Inc.: Employment, Equity Ownership. Elkins:Genentech, Inc.: Employment, Equity Ownership. Lau:Genentech, Inc.: Employment, Equity Ownership. Go:Genentech, Inc.: Employment, Equity Ownership. Scales:Genentech, Inc.: Employment, Equity Ownership. Yu:Genentech, Inc.: Employment, Equity Ownership. Chesi:Genentech, Inc.: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Merck: Research Funding. Bergsagel:Genentech, Inc.: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Merck: Research Funding. Ebens:Genentech, Inc.: Employment, Equity Ownership, Patents & Royalties.
Retrospective Database Analysis of the Effect of Zoledronic Acid (ZOL) On Skeletal-Related Events (SREs) in Patients (Patients) with Multiple Myeloma (MM).
Authors: Henk Henry J , Kaura Satyin , Perez Jose Ricardo , Becker Laura
Published: October 2019

Abstract 3881

Poster Board III-817

Background

For MM patients with malignant bone lesions (BM), SREs including pathologic fracture, spinal cord compression, hypercalcemia of malignancy, and radiotherapy and/or surgery to bone are associated with significant morbidity and mortality and reduced quality of life. ZOL is an IV bisphosphonate (BP) proven to reduce and delay incidence of SREs in several tumor types. This study was designed to assess the benefit of long-term ZOL use in a real-life setting.

Methods

Claims-based analysis of commercial and Medicare data from a large US managed care plan and a 45 health-plan database was used to evaluate SRE rates, time from BM to 1st SRE, and mortality in patients treated with ZOL or no IV BP therapy. Patients older than 18 years with MM and BM diagnosed between Jan 2001 and Dec 2006 were included. Treatment Persistency was defined as the absence of a >45 day gap between ZOL administrations. Continuous enrollment in the health plan for 6 months before and no prior evidence of BM or IV BP use were required. When assessing mortality, patients with a date of death less than 30 days following index date were excluded. Patients were followed until they disenrolled from the plan or to the end of the study's follow-up period. In this study, SREs were defined as evidence of pathologic fracture, spinal cord compression, and radiotherapy and/or surgery to bone.

Results

The study sample included 1,655 Patients with a mean age of 61.7 ± 11.9 years; approx. 64% were treated with ZOL and 36% with no IV BP. Incidences of SREs and mortality rates were both greater in the no IV BP group (incidence rate ratio [IRR] = 1.58; p-value<0.001 and mortality rate = 1.71; p-value=0.0234) vs. the ZOL groups. Longer persistency with ZOL was associated with a lower risks of first SRE compared with no IV BP (trend test p-value=0.0025) [TABLE 1].

Conclusions

This study showed that in MM Patients with BM, ZOL use was associated with a lower risk of SREs, including fractures, and lower mortality rates. In addition, longer persistence was found to be associated with lower risk of SRE.

Disclosures:

Kaura: Novartis: Employment, Equity Ownership. Perez:Novartis: Employment, Equity Ownership.
Thromboembolic Events (TEE) with Lenalidomide-Based Therapies for Multiple Myeloma (MM): Emory Experience.
Authors: Nooka Ajay K , Kaufman Jonathan L. , Heffner Leonard T , Gleason Charise L. , Lonial Sagar
Published: October 2019

Abstract 3888

Poster Board III-824

Introduction

Lenalidomide is a derivative of thalidomide with an additional amino group at position 4 and removal of a carbonyl group that has enhanced efficacy and reduced toxicity relative to its parent compound. However, studies have reported the incidence of TEE from 3-23.8%. We proceeded to evaluate incidence and risk factors of TEE associated with lenalidomide-based therapies in patients with multiple myeloma at our institution.

Methods

We reviewed 152 records of patients that were prescribed lenalidomide from prescribing information obtained from Celgene pharmaceuticals as well as reviewing patient information from all clinical trials from 2004 until October 2008. IRB approval was obtained. 146 patients (pts) were included in study after excluding 6 pts in whom lenalidomide was used for non-myeloma indications. Lenalidomide was indicated for induction in 22 (15%) pts and for maintenance/salvage in 124 (85%) pts.

Results

81 (55.5%) pts were male and 65 (44.5%) were female. White pts (65%) contributed to majority of our pt population. Median age (range) is 62 months (23-87); stage III disease is seen in 23 pts (22%); median (range) β-2 microglobulin is 2.68 (0.8-43.51) and median (range) creatinine is 1.05 (0.6-21). Pts received a median (range) of 7 (1-58) cycles. Overall ten (6.8%) TEEs were observed including nine venous TEEs (6.12%) and one arterial TEE (0.68%). Nine pts developed TEE despite being on ASA prophylaxis. Median (range) time to event was 17 weeks (4-158). Median (range) cycles of lenalidomide before the event were 3.5 (1-38). 60% of events took place in the first 4 months of initiation of therapy. On univariate analysis, erythropoietin use vs. none (21.4% vs. 5.3% p=0.023); median number of cycles ≥7 vs. <7 (11.1% vs. 2.7% p=0.044) and previous history of DVT vs. none (20% vs. 4.1%; p=0.014) were identified as significant risk factors. Steroid doses, BMI were not identified as risk factors. On multivariate analysis, age <60 (HR 0.11 95%CI 0.00-0.50; p = 0.021) had a significant protective impact on developing TEE. Median survival (range) in pts with TEE is 102 months (100.4-103.6) and pts without TEE is 99 months (79.38-118.62); log rank 0.125.

Conclusion

Neither high dose steroids nor the BMI were identified as risk factors for TEE. All pts with venous TEE had high risk factors validating the risk model of IMWG. No impact on overall survival was seen between pts with TEE and pts without TEE.

Disclosures:

Kaufman: Celgene: Consultancy, Research Funding; Millenium: Consultancy; Genzyme: Consultancy; Merck: Research Funding. Heffner:Millenium: Honoraria. Gleason:Millenium: Consultancy. Lonial:Celgene: Consultancy; Millennium: Consultancy, Research Funding; BMS: Consultancy; Novartis: Consultancy; Gloucester: Research Funding.
Charlson Comorbidity Index Is An Independent Prognostic Factor Among Elderly Patients with Diffuse Large B-Cell Lymphoma (DLBCL).
Authors: Takeuchi Jin , Hojo Atsuko
Published: October 2019

Abstract 3923

Poster Board III-859

Introduction

Wide use of rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) has improved the clinical outcome for elderly patients with DLBCL; however, a higher prevalence of coexisting disorders remains a problem. Correlation between their comorbidities and prognosis has not yet been well investigated.

Patients and methods

We retrospectively analyzed all patients over 65 years old who had been newly diagnosed with DLBCL at our institution from 2001 to 2008. To assess their comorbid medical status, we calculated the Charlson Comorbidity Index (CCI) for patient excluding primary disease. Prognostic factors were identified by Cox proportional hazards regression model. We classified patients into a low CCI group (CCI 0-1) and a high CCI group (CCI 2 or higher). Kaplan-Meyer curves for each group were evaluated by logrank test.

Results

A total of 80 patients were enrolled in this analysis. The median age was 73 (range 66-90) and the median observation period was 28 months (range 4-90 months). 62 patients (77.5%) were treated with R-CHOP, 15 (18.6%) underwent some other regimen, and 3 (3.8%) were given best supportive care only. According to revised International Prognostic Index (r-IPI), 43 patients were in the good risk group and the others were in the poor risk group. The estimated 3 year over all survival (OS) rate for these groups were 90% and 45% (p<0.0001). As for CCI, 14 patients (17.5%) were assigned to the high CCI group. Multivariate analysis revealed high CCI was associated with worse OS, while independent of r-IPI [Hazard Ratio (HR) 3.20, 95% Confidence interval (CI) 1.28-7.41, p=0.0145]. Among r-IPI poor risk patients, the high CCI group was inferior to the low CCI group for the 3 year OS rate (14% vs 56% p=0.0358), whereas this was not significant among r-IPI good risk patients (69% vs 94% p=0.0617).

Conclusions

Among elderly patients with DLBCL, high CCI is independently associated with poor survival. Patients having both poor r-IPI and high CCI may need discrete strategies.

Disclosures:

No relevant conflicts of interest to declare.
Metalloproteinase Inhibitors Inhibit the Release of Soluble CD27 by Waldenström's Macroglobulinemia Cells.
Authors: Zhou Yangsheng , Liu Xia , Gong Ping , Xu Lian , Ciccarelli Bryan , Yang Guang , Patterson Christopher J , Treon Steven
Published: October 2019

Abstract 3942

Poster Board III-878

Waldenström's macroglobulinemia (WM) is characterized by bone marrow infiltration with lymphoplasmacytic cells (LPCs), and increased presence of mast cells. CD27 is a marker of memory B-cells, and is heterogeneously expressed on the cell surface of WM cells. In recent studies, we showed that the soluble CD27 (sCD27) is produced by WM LPC and is a faithful marker of disease burden in WM patients. Importantly, sCD27 triggers via CD70 the expression of CD40L on neighboring Mast Cells, which in turn supports the growth and survival of WM LPC. sCD27 therefore represents a promising target for the treatment of WM. The mechanism for sCD27 release in WM remains to be elucidated, but is likely cleaved from cell surface CD27. We therefore examined the effects of various matrix metalloproteinase (MMP) inhibitors on the production of sCD27. sCD27 levels were measured by ELISA from supernatants of cultured BCWM.1 and BL2126 B-cells transfected with a vector expressing either FLAG-tagged CD27 (pCD27-FLAG) or a control vector. PMA treatment of pCD27-FLAG transfected BCWM.1 WM and BL2126 cells led to sustained sCD27 release in cultured supernatants; in contrast, PMA treatment of control vector transfected cells showed minimal sCD27 release. Importantly, treatment of pCD27-FLAG transfected BCWM.1 WM and BL2126 cells with MMP 8 and MMP 3 inhibitors (Calbiochem) led to four-fold and two-fold decrease in sCD27 levels, respectively (Figure 1). In contrast, no significant change in sCD27 release was observed following treatment with MMP 2/9 or non-specific MMP inhibitors. These studies demonstrate that matrix metalloproteinases play an important role in sCD27 release, and provide the framework for efforts examining MMP 8 and 3 specific inhibitors in the treatment of WM.

Disclosures:

No relevant conflicts of interest to declare.
Transformation of Indolent Small B-Cell Lymphoma to Histiocytic Sarcoma: Report of Two Cases with Molecular/Genetic Evidence of Clonal Relationship Between Two Morphologically and Immunophenotypically Distinctive Neoplasms.
Authors: Wang Endi , Hutchinson Charles Blake , Huang Qin , Sebastian Siby , Rehder Catherine
Published: October 2019

Abstract 3960

Poster Board III-896

Introduction

Rare cases of histiocytic sarcoma (HS) have been reported in association with indolent small B-cell neoplasms, either concurring with or following a small B-cell lymphoma. The biologic relationship between these two morphologically and immunophenotypically distinct neoplasms in same patients remains unclear, though recent data suggest a possible “transdifferentiation” from follicular lymphoma (FL) to HS.

Patients and Methods

We investigate the clonal relationship in two cases of B-cell lymphoma with subsequent HS, using immunohistochemical stains, PCR-based immunoglobulin heavy chain (IGH) gene rearrangement/sequencing analysis and interphase FISH study on formalin fixed, paraffin-imbedded tissue sections.

Results

Case 1 is a 62-year-old female with splenic marginal zone lymphoma (SMZL) who developed HS in a groin lymph node one year after the diagnosis of SMZL. PCR/sequence analysis of IGH gene showed a monoclonal rearrangement carrying identical DNA sequences of PCR products from the spleen with SMZL and the lymph node with HS. Case 2 is a 61-year-old female with a remote history of FL who developed supraclavicular lymphadenopathy and multiple other infiltrating foci. A supraclavicular lymph node biopsy demonstrated HS. PCR analysis detected a monoclonal rearrangement of the IGH gene and interphase FISH analysis revealed IGH/BCL-2 fusion, a genetic hallmark for FL. Although negative for other B-cell associated antigen markers, HSs show partial retention of primary neoplasms B-cell lymphomas' immunoprofiles, including expression of Oct-2 in both cases, and expression of bcl-6 and enhanced expression of bcl-2 in case 2.

Conclusion

The data provide a genotypic evidence of common clonal origin between mature B-cell lymphoma and subsequent HS in the same patients, suggesting “transdifferentiation” to HS could occur in other small B-cell lymphoma, in addition to FL. The transformed HSs might have incompletely inherited primary neoplasms' expression signatures by retaining B-cell lymphomas' characteristic immunoprofile to certain extent. The exact mechanism governing the conversion of mature B-cell lymphoma to HS is largely a mystery and remains to be elucidated by more scientific studies, though a few pathways have been proposed for the process, including transdifferentiation, dedifferentiation and common progenitor models.

Disclosures:

No relevant conflicts of interest to declare.
Pten Inactivating Mutations Promote Loss of MYC “Oncogene Addiction” in a Conditional Zebrafish Model of T-ALL.
Authors: Gutierrez Alejandro , Feng Hui , Faucherre Adele , Hertog Jeroen Den , Prochownik Edward V. , Testa Joseph R. , Kanki John , Look A. Thomas
Published: October 2019

Abstract 3977

Poster Board III-913

The MYC oncogene is overexpressed in most human cases of T-cell acute lymphoblastic leukemia (T-ALL), and our laboratory previously developed a zebrafish model of MYC-induced T-ALL that closely recapitulates the most common subtype of human T-ALL, which demonstrates overexpression of TAL1 and LMO2. We have now developed a conditional zebrafish model of MYC-induced T-ALL, based on the rag2-driven expression of a MYC-estrogen receptor (MYC-ER) fusion transgene, in which T-ALL is induced by 4-hydroxytamoxifen treatment. Most cases of T-ALL in this model exhibit 'oncogene addiction' to MYC, as evidenced by the regression of established tumors when 4HT treatment is discontinued. However, the genetic determinants of 'addiction' to the MYC oncogene are unknown. Deletion of the PTEN tumor suppressor has been found to be a recurrent abnormality in human T-ALL, and we have now identified abnormalities in PTEN, PI3K or AKT in 48% of human T-ALL. Due to a partial genome duplication that occurred during evolution, zebrafish have two pten genes, pten-A and pten-B, which are both ubiquitously expressed and are largely redundant. In order to examine the consequences of pten inactivation in MYC-induced T-ALL, we mated zebrafish loss-of-function mutations in pten-A and pten-B into our rag2-MYC-ER line that also carries the rag2-GFP transgene, allowing the in vivo monitoring of tumor onset and regression. Zebrafish were raised in 4-hydroxytamoxifen beginning at 5 days post-fertilization, and tumor onset was monitored via fluorescence microscopy. At the time of tumor onset, zebrafish were removed from 4-hydroxytamoxifen, and tumor regression was monitored weekly. Although pten loss-of-function mutations did not accelerate the onset of MYC-induced T-ALL, these did affect tumor regression. We found that T-ALL underwent regression in 68% (21/31) of zebrafish whose germline pten status was wild-type, while regression occurred in only 21% (7/32) of zebrafish harboring loss of any of their germline pten alleles (p=0.0003). The effect of pten inactivation on tumor regression was phenocopied by the expression of a constitutively active murine Akt2 transgene in the MYC-ER line, indicating that the effect of pten inactivation is mediated through the activation of AKT. Our studies provide new evidence that the PTEN-PI3K-AKT pathway is an important modulator of MYC ‘oncogene addiction’ in zebrafish T-ALL.

Disclosures:

No relevant conflicts of interest to declare.
A Randomized, Controlled Two-Center Pilot Trial of a 6-Month Exercise Training Program to Treat the Post-Thrombotic Syndrome: The EXPO Pilot Trial.
Authors: Kahn Susan , Shrier Ian , Shapiro Stan , Houweling Adrielle H , Hirsch Andrew , Reid Robert , Kearon Clive , Rodger Marc , Kovacs Michael J. , Anderson David , Wells Philip S
Published: October 2019

Abstract 3984

Poster Board III-920

Background

Exercise training is an effective treatment for lower limb arterial claudication and may also have the potential to improve the post-thrombotic syndrome (PTS).

Objectives

We conducted a randomized, allocation concealed, controlled, assessor-blinded multicenter pilot trial to provide preliminary data on the effectiveness of a 6-month exercise training program in improving the PTS.

Methods

Patients aged 18-75 years with unilateral DVT diagnosed >6 months previously and ipsilateral PTS (Villalta criteria) were screened for participation in the trial at 2 centres in Canada (Montreal & Ottawa). Eligible, consenting patients were randomized to Active Training (AT), a 26-week trainer-supervised program consisting of leg strengthening, leg stretching and aerobic exercise, or Attention Control (AC), a 1-hour presentation on PTS + monthly phone follow-ups. Participants had study visits at Baseline (T0), 3 mths (T3) and 6 mths (T6) to measure generic (SF-36) and venous disease-specific (VEINES-QOL) quality of life (QOL), PTS severity (Villalta scale), leg strength (number of heel lifts) and leg flexibility (stretch angle, in degrees, for quadriceps, hamstring, gastrocnemius and soleus muscles). Within-subject changes from T0 to T6 were compared in AT vs. AC using repeated measures two-way ANOVA.

Results

From 2007-2008, 43 patients were recruited (21 randomized to AT, 22 to AC). Mean age was 47 years, 44% were male, and 49% had moderate or severe PTS. At 3 and 6 mths, PTS severity category improved in 65% of AT vs. 26% of AC (p=0.02) and 61% of AT vs. 46% of AC (p=ns), respectively. Other results are shown in Table (for all outcomes except Villalta score, + change signifies improvement from T0 to T6).

Conclusion

In our pilot trial, exercise training improved PTS severity, QOL, leg strength and leg flexibility in patients with PTS. Exercise training appears to be a promising modality to treat PTS, and a large, adequately powered trial is warranted. Funded by Canadian Institutes of Health Research

Disclosures:

No relevant conflicts of interest to declare.
Plasma Cholinesterase Activity in ITP Patients with/without Thrombosis.
Authors: Bidot Carlos J , Ahn Yeon-Soong , Esquenosi Jacob , Bidot Carlos , Ortega Camile , Horstman Larry Lawrence , Dudkiewicz Pamela B , Jy Wenche
Published: October 2019

Abstract 3997

Poster Board III-933

Introduction

In the process of immune mediated destruction, platelets may become activated and release procoagulant microparticles in ITP (Immune Thrombocytopenic Purpura). Although bleeding is common manifestation, some patients with ITP may suffer thrombotic complications, often presenting with TIA like syndromes. Brain MRI revealed findings consistent with ischemic small vessel disease in this subgroup (J Lab Clin Med 119: 334, 1992, Thromb Res 107:337, 2002). Recently acetylcoholinesterase (AChE) of RBC and/or non-specific plasma cholinesterase (ChE) was reported to be associated with the inflammation of blood vessels and may be a marker of some inflammatory states. In the present study we investigated plasma ChE activity in patients with ITP with or without thrombotic complication.

Methods

(i) Patients. We measured ChE activity in 49 patients with ITP. They were sub-grouped as having thrombosis (TBS), F/M (11/7), and non-thrombosis (Non-TBS), F/M (23/8). The TBS group included 9 with TIA like syndrome, 6 with CAD and 3 with venous thrombosis. (ii) Assay of ChE was essentially by Ellman's method. In our system, milli-absorbance units/min (mA/min) x 0.065 = umols substrate cleaved/min. Values reported here are in units of mA/min per mL plasma. Normal controls (NC, n=14) had a cutoff of 3000 mA/min per mL plasma (=mean +2SD). (iii) Sample handling. Platelet-poor plasma (PPP) was prepared by centrifuging 10 min at 1800 xg, then frozen in aliquots. For assay, it was diluted 1:20 with saline, then 5 uL and 10 uL were used in 96-well microtiter plate.

Results

(i) We observed higher level of ChE in the TBS group compared to Non-TBS in ITP. The TBS group (+/- SD) had mean value 2859 ±866, while the Non-TBS group had 2267 ±777 (units as above). This difference was significant, p<0.02. (ii) In TBS groups, we compared TIA subgroup with other TBS subgroup and observed that the n=9 patients with TIA had higher activity compared to the other TBS: 3250 vs 2466 mA/min per mL plasma. However, this difference did not reach significance in this small patient population. Further, 5/9 TIA patients (66%) had ChE activities >3000 (normal cutoff values) compared to only 2/9 (22%) of those with other TBS >3000.

Conclusion

(i) The ChE activity of ITP patients with TBS is significantly increased compared to Non-TBS in ITP patients. It has been suggested that Blood ChE/AChE may reflect some inflammatory, prothrombotic states. (ii) ITP patients with TIA exhibited higher ChE activity among TBS subgroups in ITP, suggesting that ChE activity may serve as a useful biomarker in TIA like syndrome associated with ITP. However, further study in a larger number of patients is needed to confirm these preliminary findings.

Disclosures:

No relevant conflicts of interest to declare.
Soluble Monomeric Von Willebrand Factor A1A2A3 (R1450E) Mutant Fragment Enhances Shear-Induced Platelet Aggregation and Platelet Adhesion to Fibrin(ogen) Via αIIbβ3 Under High Shear Stress.
Authors: Cruz Miguel A. , Sowa Katie E. , Smith Scott M.
Published: October 2019

Abstract 4025

Poster Board III-961

Recently, we described that the gain of function mutation R1450E in the A1 domain of von Willebrand factor (VWF) eliminates the formation of catch bond with glycoprotein (GP)Ibα, prolonging the bond lifetimes at low forces. Because those studies were performed with the mutant immobilized on a plastic surface, we further characterize the effect of this mutant on platelet function in solution and under shear stress. Both wild type (WT) and mutant A1A2A3 proteins were expressed in HEK293 cells and purified to homogeneity. The monomeric state of A1A2A3 proteins were assessed by gel filtration chromatography and neither of the proteins had formed dimers or any higher order aggregates. The recombinant A1A2A3 mutant bound spontaneously to GPIbα without the modulator ristocetin with a half-maximal binding observed at 65 ± 8 nM. This apparent dissociation constant was comparable to that of WT (50 ± 10 nM) in the presence of ristocetin. The mutant failed to induce spontaneous platelet aggregation under stirring conditions, and blocked 100% ristocetin-induced platelet agglutination (RIPA) at concentration of 250 nM. At the same concentration, the mutant increased shear-induced platelet aggregation (SIPA) at 500s-1 and 5000s-1 shear rates, reaching 42% and 66%, respectively, while SIPA did not exceed 18% in the presence of WT. The anti-αIIbβ3 antibody 7E3 blocked the effect of the mutant on SIPA. Blood was then incubated with the mutant (250 nM) and perfused over a surface coated with fibrin(ogen) at different shear rates. Blood containing WT resulted in <10% surface coverage by platelets after 1.5 minutes while platelets from blood containing the mutant rapidly bound covering 100% of the fibrin(ogen) surface area at 1500s-1. At shear rate of 2500s-1, surface coverage was 20% for the mutant and 0% for WT fragment. EDTA and antibodies 6D1 (GPIbα) and 10E5 (αIIbβ3) effectively blocked mutant-mediated platelet adhesion and thrombus formation under high shear rates. The addition of ristocetin (0.5 mg/ml) to whole blood prior perfusion reproduced the effect of the mutant. Here, we describe an A1A2A3 mutant that bound spontaneously to GPIbα but affected differently RIPA and SIPA. These results suggest that hydrodynamic forces directly act on the GPIbα-mutant A1A2A3 complex, regulating signaling. In addition, platelet activation induced by the binding of soluble mutant A1A2A3 or plasma VWF results in αIIbβ3-mediated platelet adhesion to fibrin(ogen) under high shear rates.

Disclosures:

No relevant conflicts of interest to declare.
Transfection of Human Platelets Down-Regulates Endogenous mRNA.
Authors: Kondkar Altaf A , Hong Wei , Bergmeier Wolfgang , Herman Jay H. , Jin Ying , Nagalla Srikanth , Bray Paul F.
Published: October 2019

Abstract 4026

Poster Board III-962

Platelets are anucleate and, as such, lack the capacity for transcribing and expressing exogenously introduced genes or cDNAs. However, platelets contain megakaryocyte-transcribed mRNAs and respond to physiological stimuli by translating mRNA into protein. Compared to the megakaryocyte, the relative contribution of platelet translation to the platelet proteome is unknown. However, it is noteworthy that platelets in Blood Bank storage conditions increase their levels of integrin β3 over time and that the half-life of some mRNA is longer in platelets than in nucleated cells (Thon et al, Transfusion 2009). Considering the potential clinical and research utility of manipulating platelet gene expression, we tested the feasibility of transfecting platelets in-vitro with a fluorescently (FAM)-labeled siRNA for GAPDH as assessed by flow cytometry. We tested both electroporation and Lipofectamine with both washed platelets and platelet-rich plasma (PRP) using a variety of conditions. Our studies demonstrated optimal transfection efficiency at 24 hours using 2 × 108/mL washed platelets, 6 μL Lipofectamine and 400 pmoles siRNA. These initial studies demonstrated that 8.4% of platelets were transfected with the FAM-labeled siRNA compared to control platelets without Lipofectamine. Transfected platelets were then isolated by cell sorting. Changes in GAPDH mRNA levels were determined by TaqMan gene expression assays using18S RNA as an endogenous control. Two independent experiments demonstrated a 40% reduction in GAPDH mRNA in platelets transfected with GAPDH siRNA as compared to a FAM-labeled scrambled siRNA. These results offer proof-of-concept that nucleic acids can be introduced into platelets by non-viral methods and that these nucleic acids can modify gene expression. Future studies to increase platelet transfection efficiency may be valuable for manipulating platelet qualities in stored platelet products or to use platelets as vehicles for delivering products to the sites of vascular damage.

Disclosures:

No relevant conflicts of interest to declare.