bluuebunny/crossref_metadata_2025 huggingface dataset:
Impact of Tyrosine Kinase Inhibitor (TKI) in Chronic Myeloid Leukemia (CML) Relapsing After T Cell Depleted Allogeneic Stem Cell Transplantation (SCT)
Authors: Ito Sawa , Battiwalla Minoo , Koklanaris Eleftheria K. , Superata Jeanine , Childs Richard , Barrett A. John
Published: October 2019

Abstract 2762

Although SCT is now uncommon treatment for CML, many patients transplanted for CML have become long term survivors and some continue to relapse late post transplant. It is therefore important to evaluate the management of relapse in CML transplant survivors in the era of TKI treatment. We studied 112 patients with Ph+ CML who underwent HLA identical sibling SCT between 1993 to 2008. The mean age was 36 years (range 13–69). Eighty (71%) were in chronic phase, 17 in accelerated phase, 5 in second chronic phase and 10 in blastic phase. Ninety-nine (88%) received myeloablative conditioning regimen with cyclophosphamide +/− fludarabine and total body irradiation and 13 received a non-myeloablative regimen. GVHD prophylaxis was with cyclosporine. Bone marrow or G-CSF mobilized peripheral blood stem cells from the donor were manipulated to achieve 4-log CD3+ cell reduction ex vivo. Peripheral blood BCR-ABL p210 product was regularly monitored by either double nested PCR (until 2003) or real time PCR (2003 to present). For molecular relapse, patients received donor lymphocyte infusions (DLI) with or without imatinib 400–600mg/day. Patients with hematological relapse received a variety of treatments including second SCT. At a median follow up of 6.2 years, 10 year-relapse free survival and overall survival were 34% and 57% respectively. Overall 49 (43.8%) patients relapsed, 28 with molecular and 22 with hematological relapse. Median time to relapse from HSCT was 379 days (range 16–3718 days). Overall survival was not significantly different between relapsed patients and non-relapsed patients. (10-year OS: 59 % vs 55%, P=0.385). Thirty-five relapsed patients (71.4%) were treated with TKI based therapy. Overall survival after relapse was significantly better after TKI based therapy compared to non-TKI based therapy. (5-year survival after relapse: 78% vs 36%, P=0.004 respectively). The benefit of TKI was greater in hematological relapse (median survival after hematological relapse 1182 days in TKI based vs 72 days in others P=0.025). At 7 years median follow up after relapse, 27 (96.4%) patients with molecular relapse are alive in major molecular remission and 20 (71%) no longer receive TKI. These results show that the outlook for relapse after SCT for CML is favorable in the TKI treatment era and that combination of TKI and DLI can achieve long-term disease free survival post relapse.Figure 1.Overall survival: relapse versus no relapseFigure 1. Overall survival: relapse versus no relapseFigure 2.Overall survival after relapse: TKI based therapy versus othersFigure 2. Overall survival after relapse: TKI based therapy versus others

Disclosures:

No relevant conflicts of interest to declare.
Reduced Response to Stromal Cell-Derived Factor-1(SDF-1) May Lead to Low Expression of p57kip2 in the Bone Marrow of Patients with De Novo Myelodysplastic Syndromes (MDS)
Authors: Zhao Youshan , Chang Chunkang , Guo Juan , Gu Shucheng
Published: October 2019

Abstract 2782

Purpose

To explore the expression of p57 in the bone marrow(BM) of patients with de novo myelodysplastic syndromes(MDS), and the role in MDS pathogenesis and prognosis, as well as the relationship between the expression of p57 and SDF-1/CXCR4 signal. Patients and Methods The expression of p57 and CXCR4 in bone marrow mononuclear cells (BMMCs) of 67 de novo MDS patients (including 46 low-risk, 21 high-risk according IPSS) were measured by real-time quantitative (RT)-PCR. BM CD34+ cell percentage was measured by flow cytometry. Besides, p57 expression was investigated when stromal cell-derived factor-1(SDF-1) was co-cultured with BMMCs from MDS cases and normal control respectively. Furthermore, comparison of p57 expression level before and after treatment in 25 MDS patients was studied. Results P57 expression was significantly decreased in MDS patients when compared to normal controls (p=0.003). Patients with abnormal karyotype showed lower expression of p57 compared to normal karyotype cases (P=0.028). A positive correlation between p57 and CXCR4 expression was investigated (r=0.609, P<0.001), and P57 expression was negatively correlated to BM CD34+ cell percentage (r=−0.393, P=0.008) in MDS patients. Additionally, P57 expression increased after treatment who received hematological response (P=0.016). P57 expression in BMMCs from normal control increased significantly when co-cultured with SDF-1 in vitro, which could be blocked by AMD3100, whereas SDF-1 induced a mild increase of p57 expression in MDS when compared to normal control (P<0.001). Conclusion Low expression of the p57 is common in MDS, which may play a role in pathogenesis and indicate poor prognosis. SDF-1 induced mild p57 expression increasing in MDS patients.

Disclosures:

No relevant conflicts of interest to declare.
Inhibitors of Mtor and PI3K Synergistically Block Plasmacytoma Cell Growth
Authors: Guenther Andreas , Burger Renate , Klapper Wolfram , Staudinger Matthias , Richter Kathrin , Ahrens Tanja , Gramatzki Martin
Published: October 2019

Abstract 2903

Introduction:

Both, the phosphoinositide-3-kinase (PI3K)-AKT pathway as well as its nutrient-dependent downstream target, the mToR (mammalian target of rapamycin) kinase, are essential for the growth and survival of malignant plasma cells. PI3K-AKT can be activated by the loss of the tumor suppressor phosphatase and tensin homolog (PTEN) or by stimulation with cytokines such as interleukin-6 (IL-6) and insulin-like growth factor-1 (IGF-1). Inhibitors of the mToR pathway like sirolimus, everolimus and temsirolimus are approved for immunosuppression and treatment of renal cell cancer. In fact, they show activity in multiple myeloma patients. However, the clinical activity of mToR inhibitors may be limited by feedback loops in tumor cells that lead to activation of AKT upon inhibition of the rapamycin-sensitive Raptor complex. Selective PI3K inhibitors (Ly294002, NVP-BKM120) as well as dual PI3K-mToR inhibitors (NVP-BEZ235) are in clinical development. Here, the inhibitory effect of a panel of mToR and PI3K inhibitors, alone and in combination, was evaluated in malignant plasma cell lines and primary samples from myeloma patients.

Results:

In five human plasma cell lines, rapamycin, everolimus, Ly294002, NVP-BKM120 and NVP-BEZ235 (kindly provided by Novartis) induced a dose-dependent growth inhibition as measured by MTS assay. Despite the observed strong anti-myeloma activity of the mToR inhibitors rapamycin and everolimus with IC50 values in the nm range, the AKT pathway was activated as indicated by increased phosphorylation at Ser473. This observation was also made in explanted plasma cell tumors of INA-6 xenografted SCID mice that were treated with rapamycin, indicating that this feedback loop is also active in vivo. Therefore, combining mToR and PI3K inhibitors could be an effective strategy to overcome rapamycin-induced AKT activation. In fact, rapamycin in combination with the selective PI3K inhibitor Ly294002 or NVP-BKM120 led to synergistic growth inhibition in plasma cell lines, as calculated by the Calcusyn™ software (Biosoft). This abrogation of AKT activation was also seen in Western blot analysis. Combined treatment also enhanced the induction of apoptosis in cell lines as well as in plasmacytoma cells. Interestingly, the activity of the dual inhibitor NVP-BEZ235 could be even further enhanced by the addition of rapamycin.

Conclusion:

First clinical trials with mToR inhibitors showed anti-tumor activity and an acceptable safety profile in patients with multiple myeloma. The data presented here suggest that a combination of mToR inhibitors with PI3K targeting compounds or the use of dual inhibitors may have a favorable therapeutic potential.

Disclosures:

Guenther: Novartis, Celgene: Consultancy, Research Funding. Gramatzki:Novartis, Celgene: Consultancy, Research Funding.
Clofarabine Containing Conditioning Regimen for Allo-SCT in AML/ALL Patients: A Survey From the Acute Leukemia Working Party of EBMT
Authors: Chevallier Patrice , Labopin Myriam , Buchholz Stefanie , Ganser Arnold , Ciceri Fabio , Lioure Bruno , Faul Christoph , Guillerm Gaelle , Finke Juergen , Huynh Anne , Schubert Joerg , Kolb Hans Jochem , Polge Emmanuelle , Nagler Arnon , Mohty Mohamad
Published: October 2019

Abstract 3004FN2

Clofarabine (CLO), a second generation purine analogue, has demonstrated an efficient anti-leukemia activity while showing a favorable toxicity profile. The aim of our study was to analyse the results of CLO as part of the conditioning regimen prior to allo-SCT for the treatment of patients with AML or ALL. This retrospective multicenter report assessed the outcome of 90 patients who received a clofarabine-containing conditioning regimen allogeneic stem cell transplantation (allo-SCT) for AML (n=69) or ALL (n=21) between November 2006 and September 2010 and reported on the EBMT registry. The median age was 42 years (range: 18–69) at transplant. The majority of patients presented with an active disease at transplant (CR1 n=8; CR2 n=16, active disease n=66). All patients had received a CLO-containing conditioning regimen (RIC n=88; MAC n=2) with the following combinations: CLO/TBI n=27; CLO/Busulfan n=10; CLO/Busulfan/ATG n=32; CLO/others drugs n=21. With a median follow-up of 14 months (range: 1–45), 2-years OS, LFS, relapse incidence, non-relapse mortality (NRM) and chronic GVHD were 28+-5%, 23+-5%, 41+-6%, 35+-5% and 38+-7%, respectively. When comparing AML and ALL patients, OS and LFS were significantly higher for AML patients (OS: 35+-6% vs 0%, p<0.0001); LFS: 30+-6% vs 0%, p<0.0001). Overall, engraftment was achieved in 84% of patients with no difference between AML and ALL patients. Patients achieving CR from an active disease were 66.5% in AML vs 40% in ALL (p=0.06). Also, 2-year chronic GVHD was 35% in AML vs 17% in ALL, p=0.32. In a Cox multivariate analysis, AML was the only factor associated with a better LFS (HR=0.37; 95%CI: 0.21–0.66, P=0.001). We conclude that the use of CLO-containing conditioning regimen for allo-SCT is an effective treatment for high-risk AML patients as CLO seems to provide higher anti-tumor and alloreactivity effects. In high-risk ALL patients, disappointing results are observed. Prospective studies are needed to evaluate the potential role of CLO as part of reduced toxicity conditioning regimens in acute leukemias.

Disclosures:

No relevant conflicts of interest to declare.
Quantitative Monitoring of EBV Viral Load in 222 Hematopoietic Stem Cell Transplant Patients: Risk Analysis and Development of EBV-Associated Post-Transplant Lymphoproliferative Diseases (PTLD)
Authors: Tang Jih-Luh , Yao Ming , Lu Meng-Yao , Ko Bor-Sheng , Huang Shang-Yi , Li Chi-Cheng , Lin Chien-Ting , Hou Hsin-An , Wu Shang-Ju , Chou Wen-Chien , Tsay Woei , Chen Yao-Chang , Tien Hwei-Fang , Jou Shiann-Tarng , Yang Yong-Li , Lin Dong-Tsamn , Lin Kai-Hsin
Published: October 2019

Abstract 3018

Background and Purposes Epstein-Barr virus (EBV)-associated PTLD is a life-threatening complication following hematopoietic stem cell transplantation (HSCT). Independent risk factors include use of ATG, acute GVHD, CMV antigenemia, T-depleted graft, and unrelated donor in our previous study. Quantitative real-time polymerase chain reaction (Q-PCR) was developed for early detection and intervention of EBV reactivation to prevent PTLD-related mortality.

Patients and Methods Between Apr 2004 and Oct 2010, EBV viral load in plasma was monitored by Q-PCR in 222 HSCT patients (total 2945 samples) in NTUH. EBV reactivation was defined as > 500 copies/mL in two consecutive assays or > 10-fold elevation than baseline level.

Results EBV reactivation occurred in 50 (22%) patients. The cumulated incidence of EBV reactivation was 28% at 1-year and 32% at 2-year. Median time to EBV reactivation was 40 days (ranges, 26–406) after SCT and median peak EBV-viral load, 10888 copies/ml (ranges, 948–3×107). The risk of EBV reactivation was significantly higher in patients receiving ATG (52% vs. 13%, p< 0.001), use of TBI (58% vs. 26%, p<0.001), mismatched donor (69% vs. 27%, p<0.001), CMV reactivation (44% vs. 19%, p<0.001) in univariate analysis. In multivariate analysis, independent risk factors include: ATG use (HR 5.44, p<0.001), TBI (HR 3.52, p<0.001), and Fludara-based conditioning (HR 3.16, P=0.01). PTLD developed in 8 patients (5%) who didn't monitor EBV viral load regularly, and two were dead.

Conclusions Monitoring of EBV viral load is a sensitive and useful tool in the surveillance of EBV-reactivation. Frequent monitoring in high-risk patients is important to prevent occurrence of EBV-PTLD.

Disclosures:

No relevant conflicts of interest to declare.
Attempting to Classify Prolonged Graft-Versus-Host-Disease According to Monocyte Activation Status in Addition to T-Cell
Authors: Kuroda Rie , Maeba Hideaki , Mase Shintaro , Araki Raita , Fujiki Toshihiro , Koizumi Shoichi , Yachie Akihiro , Nishimura Ryosei
Published: October 2019

Abstract 3045

We have reported that measuring the activation markers and homing molecules on T-cells obtained from human peripheral blood (PB) samples provides useful information for predicting acute graft-versus-host disease (GVHD) severity in affected organs. Although T-cells are major player for developing GVHD, rodent GVHD studies have demonstrated that other immune cells such as monocytes/macrophages, B-cells, and mast cells involved in the pathogenesis of acute and chronic GVHD. We, therefore, evaluated activation markers and homing molecules regularly not only on T-cells but also on monocytes in PB obtained from 31 childhood patients (more than 600 samples at various time points) receiving hematopoietic stem cell transplantation (HSCT) by multicolor flow cytometry. The following markers were used: CD69, CD25, and HLA-DR for T cell activation, CCR4, CCR5, CXCR3, CCR9, and CLA for homing markers. Inflammatory monocytes were defined as CD14dimCD16+ cells or CD14+CD163+ cells. In addition we combined the data of cytokine profiles secreted mainly by T cells such as soluble interleukin 2 receptor, or monocytes such as neopterin, or both such as tumor necrosis factor-α (TNF-α), soluble TNF-αRI, and soluble TNF-αRII. In all cases showing acute GVHD, both T-cell and monocyte activation markers were elevated. Only either T-cell or monocyte activation was not observed in acute GVHD cases. However, we have some interesting results classified according to the status of T-cells and monocytes after day 100: 1) In the cases both T-cells and monocytes were highly activated as shown in Figure 1A, tapering of immunosuppressants led to exacerbation of GVHD, and prolonged administration of the drugs including steroids were needed. However steroid response itself was relatively good. 2) In the cases only T-cells, much less monocytes, were activated as shown in Figure 1B, calcineurin inhibitors were quite effective in improving GVHD. 3) In the cases of sustained chronic GVHD, neither T-cells nor mononytes were activated as shown in Figure 1C. Response to immunosuppressants was quite low. 4) When CD4 T-cell repertoire, not CD8, became normal, tapering of drugs was successful. In all cases successfully tapered immunosuppressive drugs, elevated activation markers of T-cells and monocytes completely returned to same levels of normal volunteers. In conclusion, evaluating the activation markers and homing molecules not only on T-cells but also on monocytes, combined with cytokine profiling, might provide useful information for management of patients with prolonged GVHD.

Disclosures:

No relevant conflicts of interest to declare.
LACK of ASSOCIATION BETWEEN Race and Probability of TRANSPLANT AMONG PATIENTS Referred for Hematopoietic CELL TRANSPLANTATION (HCT) for MULTIPLE Myeloma
Authors: Sharma Manish , Bromberg Michael , Klumpp Thomas R. , Kropf Patricia , Martin Mary Ellen , Emmons Robert V. , Mangan Kenneth F.
Published: October 2019

Abstract 3129

Background:

As documented in recently published large database reviews, race appears to be a barrier to the access to HCT. Hypotheses as to why this may be the case include (but are not limited to): 1. patient preference; 2. delayed time to referral from community physicians to transplant centers; 3. delays in transplant once evaluated by a transplant center; 4. Possible increased prevalence of comorbidities among racial minorities referred for transplant. We attempt to address some of these issues by reviewing our 20-year experience with transplantation for multiple myeloma.

Methods:

We queried our core clinical database for potential associations between race and the following parameters: 1. Median interval between date of diagnosis and date of referral; 2. Median interval between date of initial visit and date of transplant 3. Probability of actually receiving a transplant following formal evaluation by a transplant physician by race; 4. Type of transplant recommended 5. Reasons for not receiving a transplant.

Results:

Between January 1990 and June 2011, 441 patients with multiple myeloma were referred to our center for consideration of HCT, of whom 293 (66%) were Caucasian, 94 (21%) were African American (AA), 27 (6%) were of unknown race, and 27 (6%) were of other races. The median interval from diagnosis to referral for transplant for AA patients was 145 days, versus 137 days for Caucasian patients (p=0.32). Fifty-three of the 94 AA patients (56%), versus 157 of the 293 Caucasian patients (54%) have received at least one transplant to date (p=0.72). The median interval between the date of the initial visit to our transplant center and the occurrence of an initial transplant was 120 days for AA, versus 150 days for Caucasians (p=0.39). The probability of being transplanted on an allogeneic or hybrid (auto-allo) initial transplant protocol was 0% for AA making it to transplant vs 6% for Caucasions making it to transplant (p=0.07). Reasons for not receiving a transplant are indicated in Table 1 (global p-value = 0.94).

Conclusions:

African American and Caucasian patients with myeloma have similar intervals from diagnosis to referral, similar intervals from referral to transplant, and are equally likely to actually receive a transplant once referral to the transplant center took place. Therefore, the reported barrier to transplantation for myeloma patients appears to be prior to referral to the transplant center.

Disclosures:

No relevant conflicts of interest to declare.
An Approach for Tailoring Diverse Therapeutic Inducers of Fetal Globin to Genetic Modifier Profiles,
Authors: Perrine Susan P , Chui David H.K. , Sangerman Jose I , Boosalis Michael S , Faller Douglas V
Published: October 2019

Abstract 3188

The clinical severity of the beta thalassemia syndromes and hemoglobinopathies can be dramatically modified by up-regulation of basal fetal globin expression through co-inheritance of 3 influential genetic modifiers, or by fetal globin-inducing therapeutics. One approved therapeutic, Hydroxyurea (HU), benefits some patients, but does not reduce anemia enough to achieve transfusion-independence in many thalassemia patients, and additional HbF-enhancing therapies are needed which can be applied in combination regimens without added toxicity. A challenge to successful application of HbF-inducing therapies is the broad genetic heterogeneity, which produces variable baseline HbF levels, and, to date, unpredictable responsiveness to therapeutics among individual patients. Therapies tailored to genetic modifiers (QTL) which modulate baseline HbF levels would allow rational treatment selection for specific subsets of patients. GWAS screening of 1000 patients in diverse populations, and analyses of patients enrolled on two recent clinical trials in sickle cell disease and beta thalassemia, demonstrated that modifiers in the 3 most influential QTLs which increase HbF or F-cells occur commonly, in 30–50% of patients, with BCL11A polymorphisms occurring in 20–30%. Using molecular modeling and high-throughput screening of chemical libraries, we recently discovered 8 therapeutics (6 clinical-stage or approved) which enhance HbF expression through different mechanisms, including displacement of a repressor complex containing HDAC-3 (RB7) or suppression of BCL11A mRNA (MS-275). Two pan-HDAC inhibitors (Butyrate and MS-275) profoundly decrease the 3 BCL11A isoforms by 80–100% in normal erythroid progenitors, while other HDAC inhibitors (LBH389, SAHA) have no effect or even increase BCL11A expression. Decreases in BCL11A provide a favorable effect, similar to the BCL11A QTL, increasing both baseline HbF levels and responsiveness to HbF-inducing drugs. Other inducers (DLT, Benserazide, NSC95397, RB16, ST20) induce the gamma-globin promoter without epigenetic effects. MS-275, DLT, and RB7 increase the promoter activity by 5–6 fold in normal progenitors, while prior generation short chain fatty acid agents induced by 2-fold. This small but diverse therapeutic pipeline, encompassing different mechanisms of action, now allows: 1) epigenetic and/or non-epigenetic gamma-globin induction; 2) significantly higher induction than prior generation inducers; and 3) potential drug combinations which may benefit those patients who do not have favorable QTL polymorphisms. Individual therapeutics can now be investigated in genotyped subjects to provide a basis for tailoring specific inducer combinations to QTL profiles, offering potential for higher therapeutic benefit.

Disclosures:

No relevant conflicts of interest to declare.
Acute GVHD in AML and MDS Patients Receiving Matched Related Donor (MRD) Reduced-Intensity Conditioning Allogeneic Hematopoietic Progenitor Cell Transplant (RIC-AHPCT) Correlates with Major Histocompatibility Complex Class I-Related Molecule A (MICA) Gene Polymorphisms,
Authors: Sobecks Ronald , Zhang Aiwen , Rybicki Lisa , Thomas Dawn , Kawczak Paul , Kalaycio Matt , Andresen Steven , Pohlman Brad , Dean Robert , Copelan Edward A. , Hanna Rabi , Duong Hien , Maciejewski Jaroslaw P. , Bolwell Brian J. , Askar Medhat
Published: October 2019

Abstract 4072

Donor immune effector cells including T and NK cells have been implicated in the development of GVHD after AHPCT. MICA is a ligand recognized by the activating receptor NKG2D that is expressed on the surface of NK, NKT, CD8+ and TCRγδ+ T cells. Allelic variants of MICA due to a single amino acid substitution at position 129 in the alpha2 domain have been reported to result in large differences in NKG2D binding. MICA alleles with a methionine (M) or valine (V) have been classified as having strong or weak binding affinity for NKG2D, respectively. It has been suggested that these variable affinities affect thresholds of NK cell triggering and T cell modulation. Homozygosity of V alleles (VV) has been associated with chronic GVHD (Boukouaci et al. Blood 2009;114:5216–5224). However, the effect of such polymorphisms on outcomes after RIC-AHPCT is not clear. We studied 31 patients (20 AML and 11 MDS) who had MRD RIC-AHPCT with fludarabine/low-dose TBI conditioning. All patients received peripheral blood stem cells and GVHD prophylaxis consisted of a calcineurin inhibitor and mycophenolate. Genotyping was performed retrospectively on patients' DNA samples by rSSOP to determine MICA 129 dimorphisms and they were then categorized as having VV (n=12), MV (n=17) or MM (n=2) dimorphisms. Post-transplant outcomes were compared between patients with VV (weak) vs. VM/MM (mixed/strong binding affinities). Outcomes were estimated using the cumulative incidence method and compared between groups with the Pepe-Mori test. Patients in the VV group had significantly less grade 3–4 acute GVHD (0 vs. 26%, respectively, p=0.022) and a trend to less chronic GVHD (8 vs. 37%, respectively, p=0.07) than the VM/MM group (see Figures).

There were no differences between these groups regarding pre-transplant patient characteristics, CD34+/TNC doses, neutrophil or platelet engraftment, CMV/other infections, relapse, relapse mortality, non-relapse mortality, relapse-free or overall survival. We conclude that assessment of MICA gene polymorphisms in MRD RIC-AHPCT patients may have important implications for predicting GVHD. Those with a MICA dimorphism indicating weak binding affinity (VV) for the NKG2D activating receptor may have less alloreactive recipient immune effector cells that decrease the risk of developing GVHD. Further investigation of this observation with larger study populations is warranted.

Disclosures:

No relevant conflicts of interest to declare.
NADPH Oxidase Regulates Cytarabine-Induced Apoptotic Death in Acute Myeloid Leukemia Cells
Authors: Khan Nazmul H , Sexton Kevin J , Grimm Melissa J , Segal Brahm H , Vigil Carlos E
Published: October 2019

Abstract 4258

Background:

Cellular metabolism and oxidative stress are important in the biology and pathophysiology of malignancies. Both increased reactive oxygen species [ROS] levels and induction of anti-oxidative pathways have been described in several malignancies, and may be modulate tumor biology and susceptibility to chemotherapy. Limited studies point to metabolic pathways, including ROS production, influencing pathogenesis and chemo-sensitivity of leukemia. NADPH oxidase is a critical enzyme in antimicrobial host defense and its activation results in ROS generation in myeloid leukemia cells. Our prior studies show that NADPH oxidase can activate Nrf2, a transcriptional factor that induces anti-oxidant and cytoprotective pathways. However the role of NADPH oxidase in chemotherapy-mediated apoptosis induction in leukemic cells is not well-known.

Hypothesis:

NADPH oxidase-derived ROS will increase sensitivity of AML cells to chemotherapy, whereas Nrf2 will be associated with chemotherapy resistance

Methods:

We evaluated the role of NADPH oxidase and Nrf2 in regulating cytarabine-induced cell death in wild-type [WT] and engineered PLB-985 cells, a human acute myelomonocytic leukemia cell line derivative. NADPH oxidase-deficient PLB-985 cells were generated by recombination with mutant gp91phox, a necessary component of NADPH oxidase. Nrf2-deficient cells were generated by shRNA (Nrf2shRNA) and depletion (>70%) of Nrf2 mRNA was confirmed by quantitative-PCR. WT and engineered PLB-985 cells were treated with cytarabine (12.5 to 750ng/ml for 24 – 48 hours) and cell death was determined by trypan blue exclusion and Annexin V/7-AAD staining.

Results:

NADPH oxidase-deficient PLB-985 cells were significantly more resistant to cytarabine compared to WT cells. Cytarabine (500 ng/ml for 48h) induced apoptotic cell death in 25% of NADPH oxidase-deficient vs. 53% of WT PLB-985 cells. Additional dose-response studies confirmed a significant effect of NADPH oxidase in potentiating cytarabine-induced cell death. Nrf2shRNA PLB-985 cells had either similar or modestly increased susceptibility to cytarabine-induced cell death compared to WT PLB-985 cells with empty vectors. NADPH-deficient/Nrf2shRNA PLB-985 cells had similar susceptibility to cytarabine as NADPH-deficient cells with empty vector.

Conclusions:

Our results show that NADPH oxidase potentiates apoptotic cell death by cytarabine in a myelomonocytic leukemia cell line. However, we did not observe a consistent effect of Nrf2 depletion on apoptotic cell death by cytarabine. These studies suggest that modulation of redox-stress may be a potential therapeutic approach in AML that merits further study.

Disclosures:

No relevant conflicts of interest to declare.
An Evaluation of Septicemia During Outpatient Consolidation Chemotherapy for Acute Myeloid Leukemia
Authors: Saini Lalit , Minden Mark D. , Schuh Andre , Yee Karen , Schimmer Aaron D , Gupta Vikas , Murray Cindy Susan , Brandwein Joseph
Published: October 2019

Abstract 4268

Introduction:

Ambulatory chemotherapy for acute myeloid leukemia (AML) is believed to reduce exposure to nosocomial multi-drug resistant organisms and the incidence of septicemia.

Materials and Methods:

In this retrospective analysis we assessed the frequency of septicemia in patients receiving consolidation therapy: 256 patients received the first consolidation cycle (C1) and 217 the second consolidation cycle (C2). Patients received consolidation as inpatients or on an ambulatory basis. All ambulatory patients received infection prophylaxis with ciprofloxacin, amoxicillin and fluconazole.

Results:

71 cycles of IP and 402 cycles of ambulatory consolidation chemotherapy were administered. Rates of bacteremia were higher in the IP cohort compared to the ambulatory patients (39.4% vs. 26.6%, p=0.028). IP in C1 but not C2 had significantly more septicemia then the ambulatory cohort within that cycle. Relative to C1, C2 was associated with significantly more bacteremia (p=0.03) and more Escherichia coli isolates (p=0.023) but there was no significant difference in the rates of total Gram-positive organisms (79.2% vs. 70.4%, p=0.32), total Gram-negative organisms (20.7% vs. 28.1%, p=0.32) or Streptococcus isolates (17% vs. 23.9%, p=0.34). All Streptococcus isolates in C2 were sensitive to penicillin despite amoxicillin prophylaxis whereas all E. coli strains in C2 were resistant to ciprofloxacin.

Conclusions:

Ambulatory consolidation chemotherapy for AML is associated with a reduced incidence of septicemia. The second consolidation cycle is associated with a higher incidence of bacteremia accounted for by increased rates of ciprofloxacin resistant E. coli and penicillin-sensitive Streptococcus.

Disclosures:

No relevant conflicts of interest to declare.
Individual T-Cell Receptors of γ9δ2T-Cells Mediate Differential Anti-Tumor-reactivity
Authors: Grunder Cordula , te oome Liane CJ , Kuball Jurgen HE
Published: October 2019

Abstract 4312

Immunotherapy with innate immune cells has recently evoked a broad interest as a novel treatment option for cancer patients. γ9δ2T-cells are an emerging innate cell population with strong anti-tumor-reactivity and a promising candidate for immune interventions. However, the molecular basis of recognition remains unclear as well as whether individual γ9δ2 clones have an advantage as compared to the bulk population in terms of anti-tumor-reactivity. Therefore, bulk γ9δ2T-cells were cloned and tested for reactivity against a broad panel of tumor cells. Between different clones a high variability in recognition pattern was observed in terms of specificity and functional avidity. A number of clones were more potent in tumor recognition while others were weaker than the original bulk population. Thus, we intent to elucidate the molecular basis of observed differences among anti-tumor-reactive clones. The contribution of NK-receptors to γδT-cell activation was verified but could not fully explain their reactive abilities. Therefore, we hypothesized that the diversity within the γ9δ2T-cell receptor (TCR) itself contributes to the differential activity of examined γ9δ2T-cell clones. Hence, clone derived γ9δ2TCRs were expressed in Jurkat- and peripheral blood T cells and indeed: individual γ9δ2TCRs mediated a distinct specificity and functional avidity. By exchanging δ-chains among TCR-transduced T-cell clones with constant γ-chain we demonstrate that distinct δ-chains mediate different functional avidity. Sequence alignments revealed that this phenomenon is selectively caused by differences in the δCDR3 region. Accordingly, alanine-scanning-mutations within δCDR3 were performed. Structurally important residues were identified as well as residues involved in regulating functional avidity, suggesting their importance in antigen-recognition.

Disclosures:

No relevant conflicts of interest to declare.
Preclinical Safety Pharmacology of Baxter’s Longer Acting rFVIII (BAX 855)
Authors: Dietrich Barbara , Kubik Susan , Ehrlich Hartmut J. , Scheiflinger Friedrich , Schwarz Hans Peter , Muchitsch Eva-Maria
Published: October 2019

Abstract 4357

Baxter has developed a PEGylated recombinant human factor VIII conjugate by modifying the FVIII molecule with polyethylene glycol (PEGylation). The product is derived from a CHO cell line using a plasma-protein-free method and a virus inactivation step. The objective of this preclinical study-program was to evaluate the safety of Baxter’s longer acting rFVIII in different species. The thrombogenic potential of Baxter’s longer acting rFVIII was evaluated in the rabbit stasis model developed by Wessler. Two lots of Baxter’s longer acting rFVIII were used to demonstrate consistent safety between different batches. Advate served as the control item. Baxter’s longer acting rFVIII was not thrombogenic in this preclinical model at a dose of 900 U/kg. There was no evidence of thrombogenic potential after intravenous treatment with either the test item or Advate, the active reference item. The effects of Baxter’s longer acting rFVIII on body temperature, heart rate, blood pressure, respiratory variables or QT, QTcf, PR and/or QRS intervals and respiratory system (intra-thoracic pressure) was evaluated in eight male, conscious telemetered cynomolgus monkeys. Baxter’s longer acting rFVIII was given at 150 and 600 U/kg/day to male monkeys by intravenous administration. Baxter’s longer acting rFVIII did not cause any adverse clinical, respiratory or cardiovascular effects and was very well tolerated at all dose levels tested. In conclusion, Baxter’s longer acting rFVIII did not cause any thrombocenic events or adverse clinical, respiratory or cardiovascular effects and was very well tolerated at all dose levels.

Disclosures:

Dietrich: Baxter Innovations GmbH: Employment. Kubik:Baxter Innovations GmbH: Employment. Ehrlich:Baxter Innovations GmbH: Employment. Scheiflinger:Baxter Innovations GmbH: Employment. Schwarz:Baxter Innovations GmbH: Employment. Muchitsch:Baxter Innovations GmbH: Employment.
Black Cohosh Induced Pancytopenia: Case Report
Authors: El Amil Zeina G , Butera James N
Published: October 2019

Abstract 4383

Introduction:

Black cohosh (known as both Actaea racemosa and Cimicifuga racemosa), a member of the buttercup family is a perrenial plant that is native of North America. It has been widely used to relieve premenstrual problems, menstrual cramps and to control hot flushes and other menopausal symptoms. The mechanism of action of the black cohosh is not fully understood. Here, we report the case of a patient with pancytopenia related to the use of the black cohosh.

Case Report:

A 58 year old female patient with past medical history of dyslipidemia, presented with bruising after several months of taking black cohosh. Her complete blood count revealed a white blood cell count of 3.1×109/L (normal 3.5–11 ×109/l), hemoglobin of 10.6 g/dl (normal 11–15 g/dl), hematocrit of 31 % (normal 32–45%), mean corpuscular volume of 109 fL (normal 80–98 fl), platelets count of 37 000/μL (normal 150000–400000/μL). Her medications included lipitor, black cohosh and vitamin D. Her physical exam was remarkable only for bruising. Serum protein electrophoresis did not show any evidence of a monoclonal spike and a coomb’s test was negative. She had normal immunoglobulins level, haptogloin, LDH, liver function tests, iron studies, vitamin B12 and folate. Her prothrombin and activated partial thromboplastin times were within reference range. Her peripheral smear showed macrocytic red blood cells and decreased platelets. Her bone marrow biopsy and aspirate showed a hypocellular bone marrow (cellularity of 25–30%), with a predominance of erythroid precursors that exhibit shift toward immaturity and mild to moderate megaloblastoid changes, moderately decreased myeloid precursors, slightly decreased megakaryocytes, and normal iron stores, there was no increase in the bone marrow blasts (0.6%). She also had a flow sent for paroxysmal nocturnal hemoglobinuria, which showed normal levels of expression of CD55 and CD59 of the neutrophils and the red cells. Upon presentation, the black cohosh was stopped. Following this, her white count, hemoglobin and platelets improved slowly (figures 1,2,3,) without any further interventions, but it took over 2 years for her counts to normalize.

Conclusion:

Black cohosh is an over the counter herbal medicine that has been widely used by women to control premenstrual symptoms, menstrual cramping and menopausal symptoms. Many side effects have been described in the past but its effect on the bone marrow has never been studied. In our patient, Black cohosh caused pancytopenia that was reversible; however the recovery was very slow.

Disclosures:

No relevant conflicts of interest to declare.
Imatinib (IM) Treatment In Chronic Myeloid Leukemia (CML). Clinical Practice Limitations
Authors: Enrico Alicia Inés , Bendek Georgina , Prates Maria Virginia , Guerrero Virginia , Napal Juan Jose , Riscala Carlos , Lopez Ileana , Milone Santiago , Milone Jorge
Published: October 2019

Abstract 4454

Introduction:

CML represents 15% all of oncohematologic diseases in adults. IM changed the history of the disease. At one year of treatment, the emblematic IRIS study showed Major Cytogenetic Responses (MCyR) of approximately 87% and Complete Cytogenetic Responses (CCyR) of around 76%, with PFS to accelerated phase or blast crisis of 97.7% and 91.5%, respectively.

Objective:

To assess treatment characteristics and responses in a group of patients treated with IM in clinical practice.

Materials and Method:

113 medical records of patients with CML diagnosed between 1998–2011 from two institutions in the Argentine Republic were retrospectively analyzed.

Result:

Mean population age was 46 years old (r 18–73) 65 male, 48 female. 97% in chronic phase, the rest in accelerated phase. 31% presented comorbidities at diagnosis. Cytogenetic abnormalities at diagnosis, in addition to the classic t(9:22), included: trisomy 8 and double Philadelphia chromosome in 4 tests. Only 7 patients had qualitative BCR/ABL determined at diagnosis. 25% had received interferon, patients received IM 400 mg and only 2% received 300 or 600 mg doses. 2.6% of patients did not achieve CHR. Cytogenetic responses assessed at any time of treatment were: Major: 12%, Minor 20%, Complete 51%, None 3%, 14% were not assessed. With a mean follow-up time of 46 months, the overall survival was 75%. 10% of patients progressed to BC/AP, 11 % of patients died due to disease-related causes or comorbidities.

Conclusions:

With a mean follow-up time of 46 months for chronic phase CML, treatment with IM achieved complete cytogenetic responses in 51% of patients, and progression occurred in 10% of patients.

Disclosures:

No relevant conflicts of interest to declare.
Cytogenetic Risk Groups and Minimal Residual Disease Are Strong Prognostic Factors for Post-Transplant Outcome in Patients with Acute Myeloid Leukaemia and Myelodysplastic Syndrome
Authors: Blau Olga , Graul Katja , Sindram Annette , Thiel Eckhard , Blau Igor Wolfgang
Published: October 2019

Abstract 4482

Allogeneic stem cell transplantation (alloSCT) is a curative treatment option for patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS). Relapse after alloSCT is still a major cause for the treatment failure. Molecular genetic (FLT3, NPM1 mutations) and cytogenetic risk-categories have an important impact on the prognosis of patients undergoing alloSCT. However, it has been shown that there is a closely relationship between the level of minimal residual disease (MRD) and relapse after alloSCT in leukemia patients.

We analyzed 140 AML/MDS patients transplanted at our institution. We examined the contribution of cytogenetic aberrations and molecular genetic markers detected prior alloSCT to survival, relapse, and mortality after transplantation. Furthermore, we analyzed MRD status after consolidation therapy and in post-transplant period. We classified molecular genetic/cytogenetic status before alloSCT into 2 groups: low-risk: good and intermediate-risk karyotype, FLT3-wt, NPM1-mutated cases and high-risk: adverse-risk cytogenetic, FLT3-ITD mutated cases. A good risk karyotype was present in 8 patients; an intermediate risk in 56 patients, whereas 76 patients had a poor cytogenetic risk. 51 patients were treated with standard myeloablative conditioning regiments prior to alloSCT, 73 patients received reduced intensity conditioning and 16 non-myeloablative conditioning. 40 patients had a matched-related donor and 100 patients had a matched-unrelated donor. Overall survival (OS) in the group of patients with low cytogenetic risk was 839 days as compared with 613 days in high-risk group. The low risk cohort also showed a lower relapse (33% vs. 51%, p<0,03) and mortality rate (20% vs. 71%, p<0,003). We analyzed MRD status in all patients after consolidation therapy. MRD negative patients are characterized by favorable prognosis as compared with MRD positive patients, OS 87% vs. 53%, p<0,001. We conclude that risk-stratification combining molecular genetics and cytogenetics aberrations at the time of diagnosis with post-consolidation MRD status improve identification of high-risk category of patients. New treatment strategies are needed to overcome poor outcome of high risk AML patients, for instance, immunotherapy options like prophylactic DLI, shorter and modified immunosuppression, specific reduced intensity conditioning or new drugs like tyrosine kinase inhibitors.

Disclosures:

No relevant conflicts of interest to declare.
Sirolimus Combined with Dexamethasone for the Treatment of a Patient with Interferon Resistant Hydroa Vacciniform-Like Lymphoma
Authors: Liu Zhigang , Jia Yongqian , Gong Yuping , Guo Yong , Liu Jiazhuo , Liu Ting
Published: October 2019

Abstract 4992

Hydroa vacciniform-like lymphoma is an unusual pediatric cutaneous T-cell lymphoma, which rarely involved with adults. Chemotherapy and/or radiotherapy had little or no benefit. Patients may have a response to α-interferon. We report here an adult case with interferon resistant hydroa vacciniform-like lymphoma that has been successfully treated with sirolimus, an mTOR pathway inhibitor.

The patient is a thirty-five year old women,she begun with recurrent cutanous rash and small vesicule around her mouth and nose 3 years ago. One year before, the symptoms were exacerbated with obvious vesiculopapular eruption, edematous, blisters, ulcers, scarring and crusts in her face. Scattered vesiculopapular could be seen in her upper chest and extremities accompanied with fever and submandibular lymphadenopathy. Facial skin biopsy showed angiocentric infiltrates from the epidermis to the subjacent dermis. The infiltrate cells showed a cytotoxic T-cell phenotype, with positive TCR gene rearrangement and EBER expression in situ hybridization. EBV serum test showed EBV-IgA and IgG positive, but serum EBV-DNA was negative. Patient was given α-interferon 300 million units, intramuscularlly, two times a week, plus prednisone 30mg per day, orally. Patients' skin lesions were improved, but present recurrent episodes of papulovesicular eruptions. For the past 3 month patient had a recurrent high fever and exacerbated vesiculopapular eruptions and blisters. Laboratory test showed anemia and neutropenia, serum biochemistry and marrow examination confirmed that a lymphoma associated hematophagocytosis was complicated. Sirolimus was started at an initial dose of 1.5mg, orally, every 12 hours, combined with dexamethasone 10mg/day, intravenously. Three days later the fever begun to resolved and the skin lesion gradually subsided. Two weeks later the skin lesions disappeared and the dose of sirolinmus begun to tapered to 1.0mg, orally, every 12 hours, with prednisone 30mg/day, orally. By three month of follow-up the patient still on stable and be observed.

Disclosures:

No relevant conflicts of interest to declare.
MicroRNAs Alterations in Chronic Myelomonocytic Leukemia Are Independent of Loci of Genomic Imbalance As Detected by Oligonucleotide Array CGH (oaCGH)
Authors: Nassiri Mehdi , Czader Magdalena
Published: October 2019

Abstract 5022

Background:

Chronic myelomonocytic leukemia (CMML) remains a heterogeneous group of diseases with variable patient outcomes and no well-defined targeted therapy. We studied microRNA (miRNA) expression profiles and their relation to the diagnostic and clinical parameters in CMML, and compared it their genomic DNA alteration with oligonucleotide array CGH (oaCGH).

Design:

Bone marrow samples from 22 patients with CMML were studied. Seventeen patients presented with CMML-1 and 5 with CMML-2. Nine cases had total WBC count of less than 13×109/L. All cases were negative for BCR-ABL1 translocation. Microarray studies were performed using Agilent human miRNA microarrays (version 1.0) containing probes for 470 human and 64 human viral miRNAs cataloged in the Sanger database v9.1. Selected miRNA were validated using Quantitative real-time PCR using ABI TaqMan microRNA assay. Agilent human oaCGH microarrays (105k) containing probes for more than 99000 sequences were used to study genomic DNA.

Results:

None of the microRNAs that were significantly altered or were associated with predictive power in select CMML subtypes were mapped to loss or gain loci by oaCGH. Although few were mapped close to a specific amplified or deleted region.

Conclusions:

Significantly over- or under-expressed miRNAs are found in subtypes of CMML, that do not correlate with genomic gain and loss regions as detected by high density oaCGH. Our finding might imply that multiple underlying mechanisms at level of DNA/RNA and microRNA are responsible for heterogeneity of CMMLs.

Disclosures:

No relevant conflicts of interest to declare.