bluuebunny/crossref_metadata_2025_split huggingface dataset:
Levels of Mir-29b or Mir-101 Do Not Predict Response In Patients (pts) with Acute Myelogenous Leukemia (AML) Treated with the Combination of 5-Azacytidine, Valproic Acid and ATRA
Authors: Yang Hui , Fang Zhihong , Wei Yue , Hu Yumin , Calin George , Kantarjian Hagop M. , Garcia-Manero Guillermo 
Published: October 2019

Abstract
Abstract 1701

Introduction:
MicroRNA (miRNAs) are noncoding RNAs of 19 to 25 nucleotides in length that regulate gene expression by inducing translational inhibition and cleavage of their target mRNAs through base pairing to partially or fully complementary sites. Altered miRNA expression has been associated to various types of cancers, including leukemia. Recently it has been reported that pretreatment expression levels of miR-29b are associated with clinical response in pts with AML treated with a 10-day schedule of decitabine (PNAS 2010; 107:7473-78). These findings are significant as detection of miR-29b, if validated, could be used to select therapy in pts with AML.

Methods:
To follow on these observations, we have analyzed miR-29b and miR-101 expression levels in a cohort of patients with AML or high-risk myelodysplastic syndrome (MDS) previously treated in I/II study of the combination of 5-azacitidine (5-AZA), valproic acid (VPA) and ATRA (Blood 2007; 110:2302-08). We analyzed 45 pts, including 28 previously untreated patients. The characteristics of these pts have been previously reported (above): 8 (29%) pts achieved a complete remission and 1 (4%) partial remission. Total cellular RNA (extracted from unselected peripheral blood mononuclear cells collected before the first cycle of treatment) was used for reverse transcription reactions using TaqMan microRNA reverse transcription kit (Applied Biosystems). For real - time PCR, miR-29b and miR-101 TaqMan - microRNA assays were purchased from Applied Biosystems and analyzed with TaqMan Universal PCR Master Mix (Applied Biosystems) using an Applied Biosystems Prism 7500 Sequencing detection system. The U6 small nuclear RNA was used as internal control.

Results:
Expression levels of miR-29b and miR-101 from 45 patients were compared to 6 healthy donors. Expression levels of miR-29b was down-regulated in patients (P=0.001) (Fig. A). There were no difference in terms of miR-101 expression between patients and health donors. We then compared the miR-29b and miR-101 expression levels between patients who responded to the combination therapy versus non-responders: no differences were observed for both miR-29b (P=0.56) and miR-101 expression (Fig. B).

Conclusion:
our results fail to detect a relationship between miR-29b levels and response to 5-azacitidine based therapy. This could be explained by the fact that: 1) in our study, we used 5-azacitidine in combination versus decitabine; 2) source of RNA (peripheral blood versus bone marrow); And 3) relatively small sample size. Despite these limitations, these results indicate that larger studies need to be performed to confirm the role of miRNAs in response to hypomethylating agent based therapy.

Disclosures:
No relevant conflicts of interest to declare.
Phase II Study of Intrathecal Long Acting Liposomal Cytarabine (Depocyte®) In the Prophylaxis of Lymphomatous Meningitis In HIV-Related Non-Hodgkin's Lymphoma
Authors: Spina Michele , Martellotta Ferdinando , Berretta Massimiliano , Zanet Ernesto , Lleshi Arben , Canzonieri Vincenzo , Bulian Pietro , Bibas Michele , Antinori Andrea , Tirelli Umberto 
Published: October 2019

Abstract
Abstract 1750

Background:
Around 5% of patients with aggressive non-Hodgkin's lymphoma (NHL) develop central nervous system (CNS) progression or relapse during the course of their disease. Patients with human immunodeficiency (HIV)-related NHL often develop CNS progression despite the use of adequate prophylaxis. Liposomal cytarabine has show a significant activity in lymphomatous meningitis but there are limited data in the prophylactic setting.

Methods:
Since May 2006, we are running a prospective phase II study of intrathecal liposomal cytarabine (Depocyte®) at the dose of 50 mg in 40 patients with HIV-NHL with the aim to evaluate the feasibility and activity of this drug in the prevention of lymphomatous meningitis.

Results:
Thirty-five patients were males and the median age was 44 years (range 18–69 yrs). As far as the histological subtype of NHL, 47% of patients had a diffuse large B-cell (DLBC) NHL and 40% Burkitt NHL. Stage III-IV was diagnosed in 80% of patients and 68% of DLBC were age-adjusted IPI 2 or more. An extranodal involvement was diagnosed in 70% of patients (gastrointestinal 30%, bone 27%, spleen 10%, liver 22%, bone marrow 17%). Liposomal cytarabine was well tolerated with headache grade I to III being the most frequent side effect in only 37% of patients. Less common toxicity (all grade I) included cortical changes (5%), fever (3%), vomiting (3%), hypertension (3%), chills (3%). With a median follow up of 12.4 months only one patient (3%) with Burkitt lymphoma developed a combined systemic and meningeal relapse. Moreover, in our experience previously the present study, we used methotrexate as practical use in 426 HIV-NHL with a meningeal progression or relapse of 14% (p=0.09). The use of a liposomal formulation allowed to significantly reduce the number of lumbar injections in comparison to the standard schedules (approximately of 50%) with an improvement of quality of life of patients and with a reduction of professional exposure risk for health care staff.

Discussion:
In this first prospective study on prophylaxis of lymphomatous meningitis in HIV-NHL reported in the literature, liposomal cytarabine seems safe and active and it reduces of approximately 50% the number of lumbar punctures and exposure risk for health staff as well.

Disclosures:
No relevant conflicts of interest to declare.
Prognostic Significance of Interim 18f-FDG PET/CT for the Treatment of Diffuse Large B-Cell Lymphoma In the Post-Rituximab Era.
Authors: Yang Deok-Hwan , Min Jung-Joon , Song Ho-Chun , Jeong Yong Yeon , Chung Woong-Ki , Bae Soo-Young , Ahn Jae-Sook , Kim Yeo-Kyeoung , Bom Hee-Seung , Chung Ik-Joo , Kim Hyeoung Joon , Lee Je-Jung 
Published: October 2019

Abstract
Abstract 1799
18F-fluoro-2-dexoy-D-glucose-positron emission tomography (FDG-PET)/computerized tomography (CT) has been used for staging and monitoring responses to treatment in patients with diffuse large B cell lymphoma (DLBCL). The sequential interim PET/CT was prospectively investigated to determine whether it provided additional prognostic information and could be a positive predictable value within patients with the same international prognostic index (IPI) after the use of rituximab in DLBCL.

Patients and methods:
One hundred and sixty-one patients with newly diagnosed DLBCL were enrolled between August 2004 and December 2009 at a single institution. The assessment of the PET/CT was performed at the time of diagnosis and mid-treatment of R-CHOP chemotherapy. The clinical stage and response of the patients were assessed according to revised response criteria for aggressive lymphomas (Cheson, J Clin Oncol, 2007). The positivity of interim PET/CT was determined based on the semi-quantitative assessment of the maximal standardized uptake value (SUVmax cut-off value of 3.0).

Results:
Sixty-seven patients (41.6%) presented in advanced stage disease and 27 (16.8%) had bulky lesions. At diagnosis, 53 patients (32.9%) were classified as high/high-intermediate risk by the IPI and two patients could not check the interim response due to treatment-related mortality (TRM). Forty-three patients (26.7%) continued to have positive metabolic uptakes with a significantly high relapse rate (62.8%) compared to the patients with a negative interim PET/CT (12.1%) (P<0.01). After a median follow-up of 30.8 months, the positivity of interim PET/CT was found to be a prognostic factor for both OS and PFS, with a hazard ratio of 4.07 (2.62 – 6.32) and 5.46 (3.49 – 8.52), respectively. In the low-risk IPI group, the 3-year OS and PFS rate was significantly different in the patients with positive (53.3 and 52.5%) and negative (93.8 and 88.3%) interim PET/CT, respectively (P<0.01). These significant prognostic differences of interim PET/CT responses were consistent with the results of the patients with high-risk IPI group (P< 0.01).

Conclusions:
Interim PET/CT scanning had a significant predictive value for disease progression and survival of DLBCL in post-rituximab treatment; it might be the single most important determinant of clinical outcome in patients with the same IPI risk.

Disclosures:
No relevant conflicts of interest to declare.
Dasatinib Cerebrospinal Fluid Concentration and Plasma Pharmacokinetics: Potential for Central Nervous System Prophylaxis In Philadelphia Chromosome-Positive Leukemia
Authors: Takahashi Naoto , Miura Masatomo , Scott Stuart , Saitoh Hirobumi , Motegi Mutsuhito , Fujishima Naohito , Kameoka Yoshihiro , Tagawa Hiroyuki , Hirokawa Makoto , Sawada Kenichi 
Published: October 2019

Abstract
Abstract 1807
Dasatinib (DA) is approved for use in imatinib-resistant or intolerant chronic myeloid leukemia (CML)/Philadelphia-positive acute lymphoid leukemia (Ph+ALL) and may also be useful for central nervous system (CNS) leukemia accompanied with CML/Ph+ALL; however, little is known about the relationship between DA pharmacokinetics and its ability to penetrate the blood-brain barrier. Consequently, we measured DA plasma and cerebrospinal fluid (CSF) levels by high-performance liquid chromatography in 20 samples obtained from 11 DA-treated patients (seven Ph+ALL and four lymphoid crisis CML). DA was detected in 10 CSF samples from five patients who were treated with 100 mg QD of DA (CSF C4h of detectable group; 3.526±2.604 ng/mL, 1.11–7.95 ng/mL), which was above the IC50 level for wild type BCR-ABL positive leukemia cells in vitro (0.8 nM = 0.39 ng/mL). However, DA was not detected in 10 CSF samples from 7 patients (CSF C4h of non-detectable group; <1.0 ng/mL). The concentration ratio of CSF to plasma was 3.90% (0.42-12.23%), which approached previously reported ratios for imatinib. There were significant differences in the AUC0-4 and the plasma C4h between the CSF detectable (D) and non-detectable (ND) patients (AUC0-4: 268.29±92.452 vs. 90.83±76.45, P=0.00019 by Student t-test, Figure 1; plasma C4h: 126.15±62.58 vs. 47.41±50.935, P=0.00637 by Student t-test). Moreover, there were significant correlations between CSF C4h and AUC0-4 (P<0.01, Figure 2) and between CSF C4h and plasma C2h (P<0.001), together suggesting that penetration of DA into the CSF may depend on DA plasma concentration. To investigate any influence of pharmacogenetic variation on CSF penetration, single nucleotide polymorphisms in genes involved in DA pharmacokinetics and transport (ABCB1, ABCG2, SLC22A1, SLC22A3, and CYP3A4/5) were interrogated; however, no significant correlation between CSF levels and genotype were observed. DA has a 325 fold greater potency than imatinib for inhibiting BCR-ABL tyrosine kinase, which undoubtedly influences the efficacy of DA for Philadelphia-chromosome positive CNS leukemia; however, our data suggest that clinical DA blood level monitoring may help estimate the penetration of DA to the CSF.

Disclosures:
No relevant conflicts of interest to declare.
DNA damage-induced Leukaemic Stem and Progenitor Cell Kill with Mylotarg and Tipifarnib/Zarnestra Drug Combination In Acute Myeloid Leukemia (AML)
Authors: Jawad Mays , Yu Ning , Russell Nigel H. , Pallis Monica 
Published: October 2019

Abstract
Abstract 1824
Leukaemic stem and progenitor cells (LSPC) are relatively resistant to current chemotherapy and considered to contribute to disease progression and relapse in Acute Myeloid Leukemia (AML) patients following initial treatment. We have developed a model to study the in vitro targeting of AML LSPC by novel agents which have the potential to target LSPC whilst in a resistant niche microenvironment. Using this model, we showed that under ‘niche-like’ conditions CD34+CD38-CD123+ LSPC are less sensitive to cytarabine and to the Flt3 inhibitor AG1296. In contrast, LSPC when grown under niche support are extremely sensitive to Mylotarg (Gemtuzumab Ozogamicin), one of a few successful chemotherapeutic agents that is currently used in the clinic. We are now proposing that the combination of Mylotarg (10ng/ml) and the farnesyltransferase inhibitor, Tipifarnib/Zarnestra (5microM) is successful at further targeting the LSPC subset resulting in 70% LSPC kill (n=29 AML primary cells) after 48hr in vitro treatment compared to 31% and 12% LSPC kill in Mylotarg and Tipifarnib treated cells, respectively (p<0.0001). Moreover, stromal MS5 co-culture experiments (used to depict drug-induced cell survival in a niche-like setting) with the Tipifarnib/Mylotarg combination showed enhanced cytotoxicity even in such a resistant setting. Because activation of alternative signaling pathways maybe one mechanism that cancer cells use to evade drug-induced cell kill, we used a protein profiler assay to depict the expression of 46 known human phosphokinase proteins when treated with single and drug combination. Using the CD34+CD38- TF1A cell line, 34/46 (74%) of phosphokinase proteins that are essential for functional survival pathways (e.g. p38MAPK, ERK, JNK, AKT, STAT1/2/4/5, GSK3beta, beta-catenin, p53 etc.) were maximally reduced by the drug combination compared to housekeeping phosphoproteins, 12/46 (26%) proteins were unaffected by the drug combination and only 1/46 (the cell cycle checkpoint regulator and putative tumor suppressor Chk2) increased maximally with the drug combination. We next show that the drug combination's success is indeed characterized by the activation of DNA damage response (increase in H2AX foci by immunoflourescence), an induction of phosphoATM (by flow cytometry) leading to the activation of Chk2 and G2/M cell cycle arrest (using BrdU assay). Finally, we demonstrate that Tipifarnib may be acting as a potent P-glycoprotein inhibitor by allowing the retention of Mylotarg in cells that would otherwise efflux the drug out of the cell. In conclusion, the in vitro data presented here clearly shows why we think the Tipifarnib/Mylotarg combination can be successful in the treatment of AML and warrants further investigation to confirm its efficacy in in vivo models.

Disclosures:
No relevant conflicts of interest to declare.
Temozolomide In Acute Myeloid Leukemia: A MGMT Promoter Methylation Status–Based Treatment Stratification
Authors: Medeiros Bruno C. , Kohrt Holbrook E , Rajwanshi Richa , Gotlib Jason , Coutre Steven , Liedtke Michaela , Berube Caroline , Zhang Melody , Arber Daniel A. , Zehnder James L. 
Published: October 2019

Abstract
Abstract 3313

Introduction:
Temozolomide sensitivity is determined by the methylation status of the MGMT promoter. As most AML patients have an unmethylated MGMT promoter, response rates to temozolomide have been very disappointing in the past. We designed this exploratory study to determine whether temozolomide therapy can be tailored according to the MGMT promoter status and to test the hypothesis that protracted, low-dose temozolomide can “prime” leukemia blasts to conventional doses of temozolomide in patients with unmethylated MGMT promoter.

Patients and Methods:
Elderly patients (>60 years of age) with AML and high-risk features (relapsed/refractory, secondary AML or de novo with intermediate or unfavorable cytogenetics) were stratified according to MGMT promoter methylation status. Patients with methylated MGMT promoters received temozolomide 200mg/m2 orally for 7 days, while patients with unmethylated promoters received temozolomide 100mg/m2 orally for 14 days followed by temozolomide 200mg/m2 orally for 7 days.

Results:
36 patients (median age, 75 years) were treated with temozolomide and 31 (86%) were found to have an unmethylated MGMT promoter. Overall response rate for the entire cohort was 36% (CR – 22%, CRp – 8%, LFS- 6%). The median duration of response and median overall survival among responding patients were 29 weeks and 35 weeks, respectively. No differences in outcomes (CR rate, OS rate and duration of remission) were noted among the 2 stratification groups (Table-1) Induction deaths (within 42 days of treatment initiation) occurred in 25% (9/36) of patients and were mostly caused by disease progression. Patients with low HCT-CI scores (≤ 2) had higher ORR 43% vs.0%, fewer induction deaths (17% vs. 67%, respectively) and longer median OS (94 days vs. 25.5 days). Hematological toxicities were the most commonly observed adverse events and difficult to distinguish from disease-related cytopenias.

Conclusion:
Temozolomide therapy, stratified according to MGMT promoter methylation status, demonstrated clinical activity in elderly patients with AML and high-risk features. Protracted low-dose temozolomide may reverse the temozolomide-resistant phenotype in patients with unmethylated MGMT promoters. Future studies in better-defined populations or in combination are warranted. This trial was registered at ClinicalTrials.gov as NCT00611247.

Disclosures:
Medeiros: Schering-Plough: Research Funding. Off Label Use: Temozolomide for elderly AML.
Comparasion Between Nilotinib and Dasatinib as Second-Line Therapy for Patients with Chronic Myeloid Leukemia: A Single Center Retrospective Study.
Authors: Lobo Clarisse , Boquimpani Carla , Madeira Tania Silva , Wendling Patricia , Maximo Claudia , Lima Carlos Bernardo , Atta Elias , DE SOUZA Cravo Renata 
Published: October 2019

Abstract
Abstract 3440
Nilotinib and dasatinib are second-generation tyrosine kinase inhibitors (TKI) used in patients with chronic myeloid leukemia (CML) resistant or intolerant to imatinib. There are no randomized clinical trials comparing these drugs in this context. The aim of this study was to compare, retrospectively, the hematological, cytogenetic and molecular response in patients submitted to these second-generation TKI at Hemorio, a public brazilian institution. A total of 114 patients were analyzed, 63 received nilotinib and 51 dasatinib as second-line therapy (55.3% and 44.7%, respectively). The following variables were equally distributed between these two groups (nilotinib vs. dasatinib, respectively): male sex (54% vs. 60.8%, p=0.46), median age at diagnosis (46 vs. 45 years, p=0.76), median time in months using imatinib before the switch (45.2 vs. 44.1, p=0.96), resistance to imatinib (98.4% vs. 98%, p=0.88), presence of the mutation T315I (3.2% vs. 3.9%, p=0.09), patients in chronic phase before the switch (85.7% vs. 86.3%, p=0.93). Use of another second generation TKI, as a third-line therapy, was necessary in 30 out of the 114 patients analyzed (26.1%) because of lack of response. This modification was slightly more frequent in the group initially submitted to nilotinib (31.7% vs. 19.6%, p=0.21). Patients who used a third-line therapy were excluded from response and survival analyzes. Response rates after the second-generation TKI were similar between these two groups (nilotinib vs. dasatinib): complete hematological response until three months (77.8% vs. 87.3%, p=0.24), complete cytogenetic response until six months (21.6% vs. 22.2%, p=0.95) and 12 months (32.4% vs. 33.3%, p=0.94) and major molecular response reached before 12 months (32.7% vs. 21.6%, p=0.25). Two-year overall survival (OS) and progression free-survival (PFS) were similar between these two groups (nilotinib vs. dasatinib, respectively): 92.2% vs. 87.8% (p=0.38) for OS and 87.8% vs. 83.7% (p=0.14) for PFS. Although not statistically significant, two-year OS was inferior in the group of patients who needed a third-line therapy (70.5% vs. 95.6%, p=0.70). Our results suggest that the response and survival rates are similar between nilotinib and dasatinib as second-line therapy for patients with imatinib resistant or intolerant CML. Also, they suggest an inferior prognosis for patients who need a third-line therapy. In this way, the choice between these two TKI for second-line therapy should be guided by the clinical characteristics and the mutation status of the patient.

Disclosures:
Lobo: NOVARTIS: Research Funding.
C-Myc Inhibition Targets the Leukemia-Initiating Cells in a Tal1/Lmo2 mouse Model of T-ALL
Authors: Tesell Jessica , Kelliher Michelle , Hermance Nicole , Roderick Justine E. , Bradner James E 
Published: October 2019

Abstract
Abstract 1880
Thymic expression of the Tal1 and Lmo2 oncogenes in mice results in rapid development of T-ALL, and similar to T-ALL patients, over half the leukemic mice develop spontaneous mutations in Notch1. We have previously shown that Notch1 inhibition reduces and in some cases eliminates leukemia-initiating cells (L-ICs), however the use of anti-Notch1 therapies in the clinic has been limited due to on-target effects of Notch inhibition in the intestine. Due to the toxicities associated with Notch inhibition in vivo, we hypothesized that it may be more effective to inhibit c-Myc, a critical Notch1-regulated gene in T-ALL. We demonstrate that silencing of c-Myc in primary mouse T-ALL cells significantly prolongs survival by reducing L-IC frequency and self-renewal. A novel bromodomain inhibitor, JQ1, has been developed and shown to inhibit c-Myc in multiple hematopoietic malignancies, but its effects on LSCs or L-ICs remain unclear. Our preliminary studies reveal that JQ1 treatment prolongs survival in our mouse T-ALL model, at least in part, by reducing c-Myc mRNA and protein levels. Whether JQ1 has anti-L-IC activity in mouse T-ALL models and relapsed pediatric T-ALL patient samples will be discussed.

Disclosures:
No relevant conflicts of interest to declare.