BCR-ABL Positive Acute Lymphoblastic Leukemia Research Articles

Abstract 271: The effects of B-cell acute lymphoblastic leukemia cells on the adipose tissue microenvironment

Abstract Obesity increases the risk of developing many cancers, including breast, colon, kidney, and acute lymphoblastic leukemia (ALL). We have previously shown that ALL cells are recruited to migrate into adipose tissue, where they are protected from chemotherapy. In vitro, ALL cells induce significant changes in adipocytes which may contribute to these protective effects. However, how ALL cells affect the complex cell populations found in adipose tissue in vivo remains unknown. We therefore conducted single-cell RNA sequencing (scRNAseq) of the non-adipocyte stromal vascular fraction (SVF) from adipose tissue in obese mice with and without implanted syngeneic BCR-ABL positive ALL. Differential expression analysis was performed on individual SVF cell types to compare ALL vs. control adipose tissue and pathway enrichment analysis was used in identifying altered molecular processes between conditions. SVF from leukemic mice showed substantial differences in gene expression compared to control mice, suggesting that the ALL potentially induces changes in the microenvironment. Some of the largest differences were found in adipose tissue macrophages, and pathway enrichment analysis identified neutrophil recruitment and regulation as one of the top ten pathways upregulated in adipose macrophages from leukemic mice (4.10 fold enrichment, p<1 × 10-17 by Fisher’s exact test). Selected macrophage genes of interest in this pathway included CYBB (Cytochrome B-245 Beta), a neutrophil interaction gene that has been associated with macrophage infiltration in gastric cancer, was expressed 2.28 log2-fold higher in macrophages from leukemic compared to nonleukemic mice (p<1 × 10−99 by Wilcoxon test). ITGAL (Integrin subunit alpha L), which has been shown to be involved in neutrophil recruitment and implicated in cancer cell growth and transformation was expressed 2.85 log2-fold higher in macrophages from leukemic mice (p<1 × 10−99). Interestingly, adipose from leukemic mice showed a population of neutrophils (1.9% of SVF cells), while neutrophils were largely absent in adipose from nonleukemic mice (<0.1% of SVF cells), which is consistent with macrophage involvement in neutrophil recruitment. Our findings highlight the importance of adipose tissue in the leukemia microenvironment and show that ALL cells can influence this microenvironment in complex ways. Further work will confirm and investigate these cell-cell interactions, potentially improving our understanding of how adipose tissue contributes to cancer mortality. Citation Format: Jia Tan, Michael Cohen, Jessica Ding, In Sook Ahn, Xia Yang, Steven D. Mittelman. The effects of B-cell acute lymphoblastic leukemia cells on the adipose tissue microenvironment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 271.

Outcome Disparities Among Hispanic and Non-Hispanic Patients with Acute Lymphoblastic Leukemia

Introduction: Acute lymphoblastic leukemia (ALL) is the predominant type of leukemia diagnosed in children and accounts for approximately 20% of all cases of acute leukemia in adults. In pediatric cases, ALL generally exhibits a favorable prognosis and outcome. Unfortunately, this optimistic scenario does not extend to adults, as the majority of deaths related to ALL occur in this age group. The outcomes observed in children with ALL are linked to the favorable cytogenetic profile of their leukemia. However, as individuals age, the cytogenetic profile progressively shifts towards high-risk groups. Furthermore, several epidemiologic studies have identified ethnicity, specifically Hispanic and African American backgrounds, as independent factors associated with worse outcomes. The factors contributing to these outcomes are diverse and include limited healthcare access, insurance coverage, immigration status, treatment adherence, socioeconomic status, and timeliness of treatment initiation, among others. Additionally, individuals of Hispanic ethnicity are more prone to complex cytogenetics and Central Nervous System involvement, both of which are commonly associated with a poor prognosis. Our study aimed to assess the differences in treatment outcomes among adults diagnosed with ALL by conducting a specific comparison between non-Hispanic and Hispanic individuals. Methods: In this retrospective observational study, we collected data from the electronic medical records (EMR) of patients aged 18 years and older who received a diagnosis of Acute Lymphoblastic Leukemia between February 1, 2011, and February 28, 2020 at Ascension Seton Hospitals in Texas. The collected data included sociodemographic factors such as gender, ethnicity, and age at diagnosis, as well as clinical characteristics such as cytogenetics, immunophenotype, treatment, and overall survival. Bivariate and multivariate analyses were conducted using a chi-squared test. Statistical significance was defined as a P-value less than 0.05. Results: A total of 56 patients with ALL were identified, with 45% being non-Hispanic and 55% being Hispanic. The incidence of ALL did not show significant variation based on gender or age, but it exhibited a significant difference depending on insurance status. The analysis revealed that Hispanic patients had a significantly higher likelihood of lacking insurance coverage (75%) compared to non-Hispanic patients (25%), with a statistically significant p-value of 0.001. With the exception of one non-Hispanic patient diagnosed with T-cell ALL, almost all participants in the study had B-cell ALL. Among the patients who received chemotherapy, 44% were non-Hispanic, while 56% were Hispanic. Among patients with t(9;22)/BCR-ABL1 positive ALL, non-Hispanics represented 76% and Hispanics represented 23%. Other cytogenetic abnormalities, including CRLF2-IGH fusion, IgH rearrangement, CRLF2 rearrangement, PBX1/TCF3 fusion, t(1;19) with PBX1/TCF3 fusion, ETV6 deletion, near haploidy, and 9p deletion, were more prevalent in Hispanic patients (79%) compared to non-Hispanic patients (21%). The overall survival rates at 1 year were 64% for non-Hispanic patients and 67.7% for Hispanic patients. However, at 3 years, the overall survival rates decreased to 32% for non-Hispanic patients and 25.8% for Hispanic patients. Conclusions: Our study provides important insights into the demographic and clinical characteristics of patients with ALL and highlights notable disparities between non-Hispanic and Hispanic patients. A higher proportion of Hispanic patients lacked any form of health insurance coverage at the time of diagnosis. Interestingly, the incidence of Philadelphia-positive ALL was found to be higher among non-Hispanic patients, whereas other cytogenetic abnormalities were more prevalent among Hispanic patients. Additionally, Hispanic patients experienced lower rates of overall survival at 3 years, suggesting potential disparities in outcomes. The differences observed between Hispanic and non-Hispanic patients highlight the necessity for additional investigation and tailored interventions to address the specific challenges faced by Hispanic patients, including access to healthcare, insurance coverage, and the prevalence of unfavorable cytogenetic abnormalities.

Combined inhibition of BCR-ABL1 and the proteasome as a potential novel therapeutic approach in BCR-ABL positive acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is a disease of lymphoid progenitor cells with an often aggressive course and is commonly caused by the BCR-ABL fusion gene t(9;22) in adults. This fusion gene encodes a constitutively active tyrosine kinase that can be effectively inhibited by tyrosine kinase inhibitors (TKIs), with imatinib being the paradigmatic agent of this class. However, BCR-ABL+ ALL cells rapidly develop mutations against many of the available TKIs, and consecutive disease relapse still results in an overall unfavorable prognosis for patients with this disease. To date, allogeneic stem cell transplantation is the only known curative therapeutic option for the mostly elderly patients with BCR-ABL+ ALL. The discrepancy between the limited therapeutic armamentarium and the growing therapeutic need in an aging population is therefore a reason to test drug combinations against BCR-ABL+ ALL. In this study, we demonstrate that the combination of TKIs with proteasome inhibitors efficiently and under certain conditions synergistically exerts cytotoxic effects in BCR-ABL+ ALL cells in vitro with respect to the induction of apoptosis. Both sole and combined treatment of BCR-ABL+ ALL with the proteasome inhibitors bortezomib and ixazomib, respectively, and TKI causes a significantly greater reduction in cell viability than TKI treatment alone in both BCR-ABL+ cell lines TOM-1 and BV-173. In BV-173 cells, we observed a significant reduction in cell viability to only 1.26%±0.46% with bortezomib treatment and 1.57±0.7% with combination treatment, whereas cells treated with dasatinib alone still had a viable percentage of 40.58±2.6%. Similar results were obtained when ixazomib was applied to both cell lines, and apoptosis was induced in both cases (93.36%±2.7% apoptotic BV-173 cells when treated with ixazomib and TKI). The combination of TKI and proteasome inhibitor is efficient in vitro, potentially expanding the spectrum of therapeutic options for patients with BCR-ABL+ ALL.

Detection of ABL1 kinase Domain Mutations in Therapy Naive BCR-ABL1 Positive ALL

Background: Mutations in the ABL1 kinase domain are the main mechanism of resistance to tyrosine kinase inhibitors (TKI) in Philadelphia-positive (Ph+) leukemias. In acute lymphoblastic leukemia (ALL), a very early acquisition of mutations can be observed and reports described that mutations may exist already before TKI treatment (Hofmann, Blood, 2003; Pfeifer, Blood, 2007; Soverini, Hematologica, 2011). Initial data came from cloning or mutation-specific PCR assays, which are labor-intensive, do not detect all possible mutations and especially come with the doubt of detecting amplification artefacts. Despite the first description over ten years ago, ABL1 mutation screening is not a standard test for ALL patients before first TKI treatment. Now, the broad availability of highly sensitive next-generation sequencing (NGS) approaches allows overcoming initial limitations.Aim: To screen initial diagnosis samples of 48 BCR-ABL1 positive ALL patients for ABL1 kinase mutations by NGS.Patients and Methods: We investigated the diagnosis samples of 48 BCR-ABL1+ ALL patients (21 females, 27 males) with a median age of 62 (range: 19-85) years. Subsequent treatment data was available for 32 patients. The cohort included both patients, who had received stem cell translation (n=11) and only chemo- and/or TKI treatment protocols (n=21). At diagnosis, median blast count was 77% (12%-99%). RNA for BCR-ABL1 detection and mutation analysis was isolated from bone marrow (n=28) or peripheral blood (n=20). Six amplicons for sequencing on the MiSeq (Illumina, San Diego, CA) covered amino acid 184-510 of ABL1 and were generated from pre-amplified BCR-ABL1 . A 1% detection limit was used for analysis (minimal coverage: 400x). Mutations were proven by duplicates to exclude potential artefacts from random PCR errors.Results: Using NGS, we found well characterized ABL1 kinase domain mutations in three of the 48 (6%) initial diagnosis samples: D276G, T315I and Q252H. The percentage of mutated BCR-ABL1 transcripts were variable and not limited to small clones: D276G: 3% (332/9,725 reads), T315I: 14% (958/6,986 reads) and Q252H: 53% (3,369/7,393 reads with cag>cat, 582/7,393 reads with cag>cac).The Q252H (cag>cat) mutation had expanded to 97% of BCR-ABL1 transcripts at relapse after five months on treatment with standard protocols including imatinib, to which the mutation causes resistance. The T315I and the D276G mutation also cause resistance to TKIs (especially T315I to four TKIs). Both mutations were found in patients, who had received allogeneic stem cell transplantation and achieved complete remission, thus during follow-up there was no indication for mutation analysis. Interestingly, biochemical assays showed increased oncogenic potency or kinase activity for both mutations without TKIs (Piazza,Leukemia, 2005; Skaggs, PNAS, 2006), which would explain the mutation outgrowth before TKI induced selective pressure. We speculate that mutations, which confer resistance but reduce kinase activity, would not outgrow before TKI treatment and therefore only a subset of resistance mutations can exist in therapy naïve patients. The high turnover rate of ALL cells should allow a much faster selection of mutated clones with a relative growth advantage if compared to the situation in chronic myeloid leukemia.Interestingly, all three patients with a mutation at the initial diagnosis had a p190 transcript (3/31 [10%]), while none of the 17 patients with a p210 transcript had a mutation at diagnosis.Of note, in 12 patients we had identified one or two known ABL1 mutations per patient in the later course of TKI treatment as part of routine follow-up. Except for the Q252H mutation, we did not detect any mutation in the diagnosis sample. The relevant bases had a median coverage of 10,341x (4,620x-12,738x), which allows a sensitivity of at least 1%.Conclusions: Known resistance mutations in the ABL1 kinase domain were detected in 3/48 (6%) therapy naïve diagnosis samples in BCR-ABL1 positive ALL. The mutated clone is expected to expand rapidly if treatment with an insensitive TKI would have been chosen. This might be of clinical relevance as TKIs are one important backbone and guarantor of success for improved outcome. Using NGS allows a direct and sensitive (1%) strategy to identify patients at risk of resistance before any TKI therapy is started and to choose the best drug already in first line. DisclosuresBaer:MLL Munich Leukemia Laboratory: Employment. Meggendorfer:MLL Munich Leukemia Laboratory: Employment. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

The Promise and the Reality of Genomics to Guide Precision Medicine in Pediatric Oncology: The Decade Ahead.

Much has been written about the promise of "precision medicine," especially in oncology, where somatic mutations can influence the response of cancer cells to "targeted therapy." There have been successful examples of targeted therapy improving the outcome of some childhood cancers, such as the addition of an ABL class tyrosine kinase inhibitor to conventional chemotherapy substantially improving the cure rate for patients with BCR-ABL1 positive acute lymphoblastic leukemia. Although there are other mutations serving as putative targets in various childhood leukemias and solid tumors, effective targeted therapy has yet to be established for them in prospective clinical trials. There are also uncertainties about which "targeted therapy" to use when patients have multiple targetable genomic lesions in their cancer cells, given the paucity of data upon which to develop evidence-based guidelines for selecting and integrating targeted agents for individual patients. There are also multiple examples of inherited germline variants for which evidence-based guidelines have been developed by the Clinical Pharmacogenetics Implementation Consortium to guide the selection and dosing of medications in children with cancer. Clinical pharmacology is poised to play a critical role in both the discovery and development of new targeted anticancer agents and their evidence-based translation into better treatment for children with cancer. To embrace these challenges and opportunities of "precision medicine," clinical and basic pharmacologists must expand the depth of our science and the bandwidth of our translational capacity if we are to optimize precision medicine and advance the treatment of cancer in children and adults.

Heterogeneous BCR-ABL1 signal patterns identified by fluorescence in situ hybridization are associated with leukemic clonal evolution and poorer prognosis in BCR-ABL1 positive leukemia

BackgroundAlthough extensive use of tyrosine kinase inhibitors has resulted in high and durable response rate and prolonged survival time in patients with BCR-ABL1 positive chronic myeloid leukemia (CML) and acute leukemia, relapse and drug resistance still remain big challenges for clinicians. Monitoring the expression of BCR-ABL1 fusion gene and identifying ABL kinase mutations are effective means to predict disease relapse and resistance. However, the prognostic impact of BCR-ABL1 signal patterns detected by fluorescence in situ hybridization (FISH) remains largely unaddressed.MethodsBCR-ABL1 signal patterns were analyzed using FISH in 243 CML-chronic phase (CML-CP), 17 CML-blast phase (CML-BP) and 52 BCR-ABL1 positive acute lymphoblastic leukemia (ALL) patients.ResultsThe patterns of BCR-ABL1 signals presented complexity and diversity. A total of 12 BCR-ABL1 signals were observed in this cohort, including 1R1G2F, 1R1G1F, 2R1G1F, 1R2G1F, 2R2G1F, 1R2G2F, 1R1G3F, 1G3F, 2G3F, 1G4F, 1R1G4F and 1R4F. Complex BCR-ABL1 signal patterns (≥ two types of signal patterns) were observed in 52.9% (n = 9) of the CML-BP patients, followed by 30.8% (n = 16) of the ALL patients and only 2.1% (n = 5) of the CML-CP patients. More importantly, five clonal evolution patterns related to disease progression and relapse were observed, and patients with complex BCR-ABL1 signal patterns had a poorer overall survival (OS) time compared with those with single patterns (5.0 vs.15.0 months, p = 0.006).ConclusionsOur data showed that complex BCR-ABL1 signal patterns were associated with leukemic clonal evolution and poorer prognosis in BCR-ABL1 positive leukemia. Monitoring BCR-ABL1 signal patterns might be an effective means to provide prognostic guidance and treatment choices for these patients.

Quinacrine Depletes BCR-ABL and Suppresses Ph-Positive Leukemia Cells

Drug resistance to TKIs and the existance of CML leukemia stem cells is an urgent problem. In this study, we demonstrate that quinacrine (QC) induces apoptosis in BCR-ABL positive CML and acute lymphoblastic leukemia (ALL) cells. Interestingly, QC inhibits the colony formation of primary CD34+ progenitor/stem leukemia cells from CML patients. QC targets RNA polymerase I, which produces ribosomal (r)RNA, involving in protein translation process. Also, QC treatment prolongs CML-like mice survival and inhibits K562 tumor growth in vivo. In conclusion, we demonstrate that QC depletes BCR-ABL protein and suppresses Ph-positive leukemia cells in vitro and in vivo.

Prognostic factors of pediatric patients with Ph-positive acute lymphoblastic leukemia

目的探讨儿童Ph染色体阳性和（或）BCR-ABL融合基因阳性急性淋巴细胞白血病（Ph+ ALL）的临床特征及预后影响因素。方法回顾性分析北京大学人民医院儿科2006年12月至2016年12月收治的68例初治Ph+ ALL患儿的临床资料。采用Kaplan-Meier法进行生存分析，χ2检验及Log-rank检验评估各因素对预后的影响，多因素分析采用Cox回归模型。结果68例Ph+ ALL患儿男女比为2.1∶1，中位年龄8（1~16）岁，中位总生存（OS）时间16.8个月，中位无病生存（DFS）时间13.5个月。早期治疗反应良好率为43.9%（29/66），伴髓系抗原表达组与不伴髓系抗原表达组的早期治疗反应良好率分别为29.6%和61.3%（χ2=5.814, P=0.020）。1个疗程完全缓解（CR）率为86.2%（56/65），早期治疗反应良好组与不良组的1个疗程CR率分别为100.0%和74.2%（χ2=6.680, P=0.003）。诱导化疗期加用伊马替尼组与单纯化疗组的1个疗程CR率分别为94.9%和73.1%（χ2=5.185, P=0.024）。2年和5年的OS率分别为（61.4±7.0）%和（50.8±8.1）%，2年和5年的DFS率分别为（54.6±6.8）%和（48.6±7.3）%。单因素分析显示，Ph+ ALL患儿的2年OS率与初诊WBC、LDH水平、脾脏大小、肝脏大小、是否伴髓系抗原表达、早期治疗反应、1个疗程后流式细胞术检测的MRD水平（或BCR-ABL）、是否应用伊马替尼及不同治疗方案等因素有关（P值均<0.05），2年DFS率与LDH水平、脾脏大小、肝脏大小、是否伴髓系抗原表达、早期治疗反应、1个疗程后流式细胞术检测的MRD水平（或BCR-ABL）、是否应用伊马替尼及不同治疗方案等因素有关（P值均<0.05）。多因素分析显示脾脏肋缘下≥3 cm是影响患者OS（RR=45.7, 95% CI 1.4~1 528.2, P=0.033）及DFS（RR=52.3, 95% CI 1.6~1 725.9, P=0.026）的独立预后危险因素。结论儿童Ph+ ALL具有独特的临床和生物学特征。免疫分型中伴髓系抗原表达患儿的早期治疗反应差。早期治疗反应差的患儿1个疗程CR率低，诱导化疗期加用伊马替尼可明显提高1个疗程CR率。脾脏肋缘下≥3 cm是影响患者预后的独立危险因素。单纯化疗疗效差，化疗联合伊马替尼可以明显提高疗效。

CBP/Catenin antagonists: Targeting LSCs' Achilles heel.

Cancer stem cells (CSCs), including leukemia stem cells (LSCs), exhibit self-renewal capacity and differentiation potential and have the capacity to maintain or renew and propagate a tumor/leukemia. The initial isolation of CSCs/LSCs was in adult myelogenous leukemia, although more recently, the existence of CSCs in a wide variety of other cancers has been reported. CSCs, in general, and LSCs, specifically with respect to this review, are responsible for initiation of disease, therapeutic resistance and ultimately disease relapse. One key focus in cancer research over the past decade has been the development of therapies that safely eliminate the LSC/CSC population. One major obstacle to this goal is the identification of key mechanisms that distinguish LSCs from normal endogenous hematopoietic stem cells. An additional daunting feature that has recently come to light with advances in next-generation sequencing and single-cell sequencing is the heterogeneity within leukemias/tumors, with multiple combinations of mutations, gain and loss of function of genes, and so on being capable of driving disease, even within the CSC/LSC population. The focus of this review/perspective is on our work in identifying and validating, in both chronic myelogenous leukemia and acute lymphoblastic leukemia, a safe and efficacious mechanism to target an evolutionarily conserved signaling nexus, which constitutes a common "Achilles heel" for LSCs/CSCs, using small molecule-specific CBP/catenin antagonists.

Use of Tyrosine Kinase Inhibitors Post-Allogeneic Stem Cell Transplant in Patients with Philadelphia or BCR-ABL Positive Acute Lymphoblastic Leukemia: A Systematic Review and Meta-Analysis

Background: The use of tyrosine kinase inhibitors (TKIs) in the treatment of Philadelphia chromosome (Ph+) or BCR-ABL positive acute lymphoblastic leukemia (ALL) has improved remission rates allowing more eligible patients to proceed on to allogeneic hematopoietic stem cell transplantation (alloHSCT). Since many patients relapse following alloHSCT, some guidelines have recommended TKIs post alloHSCT (Couban, 2014, Giebel, 2016). Although some studies have demonstrated the benefits of this strategy, others have indicated that, owing to the immunomodulatory effects of TKIs, this approach may be harmful, leading to higher relapse rates. Given this uncertainty, we conducted a systematic review and meta-analysis of published studies comparing the outcomes of patients post alloHSCT who did or did not receive TKIs.Methods: We searched MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, ACP Journal Club, Scopus and conference abstracts focusing on the period during which TKIs were available (2000 to March 2016). Studies were included if they were retrospective or prospective cohort/randomized studies of adult patients with Ph+ or BCR-ABL+ ALL who underwent alloHSCT and received post-transplant TKIs. Studies that did not include a comparative group of patients who did not receive TKIs, duplicate studies, abstracts later published and studies of only pediatric patients were excluded from further analyses. Two reviewers with ALL expertise independently evaluated all abstracts and performed study selection.Results: The literature search identified 868 unique references, 195 of which were reviewed in detail. Seven studies, 6 retrospective and 1 prospective, comprising 1441 patients met all inclusion criteria (Table 1). Three studies contained one or more pediatric patients and four included patients beyond first complete remission including some with hematological relapse at the time of alloHSCT. All studies had a mix of donor sources including matched related, matched unrelated, mismatched related and mismatch unrelated. Pre-transplant conditioning was myeloablative in 3, reduced intensity in 1 and a combination of the two in the remaining 3 studies.TKIs were administered prophylactically (prior to hematological or minimal residual disease relapse) or pre-emptively (prior to hematological relapse). Data on the TKI used was not available in one study. Amongst the remaining 6 studies, imatinib at 400 - 600mg was the most commonly used TKI with dasatinib being used in 3 studies and nilotinib in 1 study. TKIs were initiated 0.5 - 60 months after alloHSCT and continued for 1-64 months after initiation.Overall, 346 patients received a TKI post alloHSCT while 1095 patients did not. Using a fixed effects model there was no difference in the relapse free survival (HR =0.838, 95% CI 0.678 - 1.036, p=0.102) or overall survival (HR=0.868, 95% CI 0.675 - 1.117, p=0.27) for those who received a TKI compared to those who did not. In contrast, there was a significant increase in relapse rates for those who were treated with TKI post-HSCT (HR 1.204, 95% CI 1.044 - 1.387, p=0.011).Conclusions: While there are compelling theoretical reasons to recommend TKIs post alloHSCT (Couban, 2014), this meta-analysis suggests that their use is not associated with improvements in overall survival or relapse free survival and may be associated with higher relapse rates. However, given the heterogeneous nature of the studies, these results must be viewed with caution. Nonetheless, the results are compelling and highlight the need for larger prospective controlled studies evaluating the role of TKI post alloHSCT in patients with Ph+ ALL. [Display omitted] DisclosuresLiew:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees.

CRLF2 Rearrangement Status in Ph-like ALL Predicts Intrinsic Glucocorticoid Resistance In Vitro that is Reversible with Targeted MAPK and PI3K Pathway Inhibition

Background:Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy and is most often of B-cell lineage (Roberts, et al. NEJM 2014). One subtype of B-cell ALL, Philadelphia chromosome-like ALL (Ph-like ALL), is BCR-ABL negative with a gene expression signature similar to that of BCR-ABL positive ALL and is prognostic for poor clinical outcomes (Roberts, et al. NEJM 2014). Ph-like ALL is often associated with rearrangements involving the cytokine receptor-like factor 2 (CRLF2) component of the thymic stromal lymphopoietin receptor (TSLPR) leading to its overexpression (Shochat, et al., JEM 2011). TSLPR is a heterodimer of CRLF2 and IL-7Rα that signals to promote the proliferation and differentiation of B-cell progenitors and acts to promote B-cell transformation in the context of Ph-like ALL (Maude, et al. Blood 2012). Glucocorticoid (GC) therapy plays a central role in the treatment of childhood ALL and resistance to GCs confers a poor prognosis (Piovan, et al. Cancer Cell, 2013). This study examined the role of TSLPR signaling in mediating primary GC resistance and the effects of downstream signal transduction inhibitors to confer GC sensitivity.Methods:Viably cryopreserved splenocytes were obtained from 19 patient-derived xenografts of Ph-like ALL banked in the Children’s Oncology Group or Children’s Hospital of Philadelphia leukemia biorepositories. Assays were also performed using the Mutz 5 Ph-like ALL cell line. Flow cytometry was used to assess the protein expression of TSLPR and GC receptor (GR). Levels of pERK and pAKT were measured by phosphoflow cytometry at baseline and following TSLP stimulation. Cells were cultured in the presence of 1µM dexamethasone (dex), a GC, with or without 1µM trametinib, a MEK1/2 inhibitor, or 1µM MK2206, a pan-AKT inhibitor, in the presence of TSLP and viability was assessed by Hoechst staining and flow cytometry at 48 hours.Results:Of the 19 Ph-like ALL samples in this study, 11 were CRLF2-rearranged (CRLF2R) and 8 were non-rearranged (CRLF2NR). CRLF2 rearrangements involved P2RY8 or IGH and 9 of 11 samples had concomitant activating mutations in JAK1 or JAK2. CRLF2NR samples expressed a variety of other translocations involving genes such as JAK2, PDGFR, and ABL1. CRLF2R cells were shown to have significantly greater TSLPR protein expression relative to CRLF2NR cells (p = 0.03). In the presence of TSLP, CRLF2 rearrangement status predicted responsiveness to dex, with CRLF2R samples demonstrating significant resistance to dex relative to CRLF2NR samples (p = 0.004). There was no significant reduction in cell viability following dex treatment in CRLF2R samples (p = 0.5), while dex effectively attenuated cell viability in CRLF2NR samples (p = 0.008). Importantly, there was no difference in GR expression between these two groups (p = 0.6). CRLF2R samples demonstrated hyperresponsiveness to TSLP stimulation, with a significant induction of pERK and pAKT that exceeded the response of CRLF2NR samples (p = 0.007 and p = 0.0005, respectively) despite no differences in basal phosphoprotein levels between the two sample groups. Inhibition of MAPK signaling with trametinib or of AKT signaling with MK2206 significantly sensitized CRLF2R cells to dex in the presence of TSLP when used in combination relative to dex alone (p = 0.0003 and p < 0.0001, respectively) and resulted in a significant reduction in cell viability relative to untreated cells (p < 0.0001 and p < 0.0001, respectively). The Mutz 5 cell line, which expresses both a CRLF2 rearrangement and a JAK2 activating mutation, was used to assess the effect of simultaneous pathway inhibition. Mutz 5 cells were treated with dex alone or dex in combination with trametinib and/or MK2206. While dex alone had no significant effect on cell viability, the addition of trametinib or MK2206 resulted in a 43% and 36% reduction in cell viability, respectively. Furthermore, combined treatment with dex, trametinib, and MK2206 resulted in a 72% reduction in cell viability, demonstrating the efficacy of simultaneous MAPK and PI3K pathway inhibition to confer dex sensitivity.Conclusion:MAPK and PI3K pathway signaling play a role in mediating primary GC resistance in CRLF2R Ph-like ALL, making these pathways potential therapeutic targets for enhancing the efficacy of GC therapy in this patient group. DisclosuresMaude:Novartis: Consultancy. Teachey:Novartis: Research Funding.

Molecular biological characteristics and prognosis analysis of bcr-abl positive acute lymphoblastic leukemia

Objective To investigate the molecular biological characteristics of bcr-abl positive acute lymphoblastic leukemia, and to evaluate clinical efficacy and prognosis. Methods 35 newly diagnosed patients with bcr-abl positive acute lymphoblastic leukemia from March 2009 to March 2014 were retrospectively analyzed. The clinical efficacy and prognosis were evaluated through comparing and analyzing the first complete remission (CR1) time, overall survival (OS) and relapse rate (RR) among different induction chemotherapy regimens, between the different gene transcripts as well as between transplantation and non-transplantation. Results 35 patients were treated with four different induction chemotherapy regimens combined with imatinib. There were 21 male cases and 14 female cases among 35 patients, and their median age was 38 years old (16-65 years old). According to the gene transcript, the patients were divided into p190 positive group including 26 cases (74.28 %) with the median gene expression level 0.582 4 (0.123 3-0.976 0) and p210 positive group including 9 cases (25.72 %) with the median gene expression level 0.623 5 (0.097 4-0.959 2). Median follow-up time was 12 months, then CR1-reaching time of the four induction chemotherapy regimens was not different statistically (P = 0.518). CR1-reaching time in p190 positive group was extended (P= 0.016), and overall survival (P= 0.167) and the relapse rate (P= 0.164) were no differences compared with those in p210 positive group. Allogeneic hematopoietic stem cell transplantation was performed in 16 morphology CR patients after chemotherapy. The median survival time of transplantation group was 32 months (7-43 months), and that of non-transplantation group was 13 months (4-18 months) (P = 0.017), but their RR difference was no statistical significance (P = 0.072). Conclusions The CR1-reaching time of bcr-abl positive acute lymphoblastic leukemia patients has no obvious difference in the four induction chemotherapy regimens combined with imatinib. The CR1-reaching time of patients with p190 positive is obviously prolonged compared with that with p210 positive, but the OS and RR have no significant difference. Allogeneic hematopoietic stem cell transplantation can improve the OS. Key words: Gene, bcr-abl; Leukemia, lymphoblastic, acute; Molecular biological characteristics; Prognosis

High Prevalence of Relapse in Australian Children with Ph-like Acute Lymphoblastic Leukemia Despite Risk Adapted Treatment

Introduction:While remission rates for childhood acute lymphoblastic leukemia (ALL) now exceed 80%, relapsed ALL remains the leading cause of non-traumatic death in children. Recently, a high-risk group of B-progenitor ALL patients has been identified. Such cases exhibit a gene expression profile similar to that of BCR-ABL1 positive (Ph+) ALL but are BCR-ABL1 negative, and also experience poor treatment outcomes. This subset, termed Ph-like ALL, is characterised by a range of genetic alterations that activate cytokine receptor and kinase signalling, allowing potential targeting by available tyrosine kinase inhibitors (TKI). The frequency of Ph-like ALL in the Australian community and the prognosis in the setting of the first MRD (minimal residual disease) intervention trial by the Australian and New Zealand Children's Haematology/Oncology Group (ANZCHOG ALL8) is unknown.Method:We retrospectively screened 250 unselected samples that were available from children diagnosed with B-ALL, for Ph-like ALL. The children, aged between 1 and 18 years, were enrolled on the ANZCHOG ALL8 trial and recruited from 2002-2011. The criteria for stratification to the high-risk group, based upon Berlin-Frankfurt-Munster (BFM) protocols, were BCR-ABL1 or MLL t(4;11) translocation; poor prednisolone response at day 8; failure to achieve remission by day 33 or high MRD (>5 x10-4) at day 79. MRD was measured by RQ-PCR for patient-specific immunoglobulin and T-cell receptor rearrangements. All patients received a standard BFM four drug induction chemotherapy regimen including a prednisolone pre-phase and intrathecal methotrexate. High-risk patients received a further three novel intensive blocks of chemotherapy followed by transplant in most cases. Patients were screened for Ph-like ALL using a custom Taqman Low Density Array (TLDA) based upon previous reports. Fusions were then confirmed by RT-PCR for 30 known fusions, Sanger sequencing, mRNA sequencing and/or FISH.Results:Ten percent (25/250) of children in this cohort were identified as having Ph-like ALL, with most fusions converging on kinase activating pathways (Table 1). Three Ph-like ALL patients were considered high-risk, the remaining 22 (88%) were medium risk. Five children with Ph-like ALL, that did not have a fusion identified by RT-PCR, are currently under further investigation. Furthermore, 15 of the 20 (75%) of rearrangements involved CRLF2 with 10 (66%) of these children relapsing. Strikingly, 56% (14/25) of children in the ALL8 cohort who were identified as Ph-like subsequently relapsed compared to 16% (36/225) who were not, with significantly worse event free survival (p<0.0001) (Figure 1).Conclusion:Here we demonstrate a significantly higher frequency of relapse amongst Australian children with Ph-like ALL compared to non Ph-like disease despite a MRD-adjusted intensification regimen. In this cohort, these children should be classified as high-risk due to high treatment failure rates with standard/medium risk regimens. Importantly, rapid identification of these patients may guide future intervention with targeted therapies, such as TKI, matched to the causative genetic lesion in this high-risk group. [Display omitted] [Display omitted] DisclosuresHughes:ARIAD: Honoraria, Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding; Novartis: Honoraria, Research Funding. Mullighan:Incyte: Consultancy, Honoraria; Cancer Science Institute: Membership on an entity's Board of Directors or advisory committees; Amgen: Honoraria, Speakers Bureau; Loxo Oncology: Research Funding. White:Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding.

Acute leukemia in adults

The prognosis of adult patients with acute leukemia has continuously improved over the years due to the introduction of new diagnostic and therapeutic procedures and progress in the field of supportive therapy. This article gives an overview of the currently available options and the clinical approach to the diagnostics and therapy of acute leukemia. The standardization as well as improvements in diagnostic procedures, in particular by immunocytological and genetic procedures, allow a more rapid determination of the exact diagnosis. In addition to age and performance status of patients, an established panel of cytogenetic and molecular markers allows an individual risk stratification for selecting the most appropriate therapeutic procedure for each patient. In acute myeloid leukemia (AML) younger patients with genetically determined intermediate and poor risk status benefit from allogeneic stem cell transplantation whereas patients in the low risk group are still primarily treated with conventional induction chemotherapy with anthracycline and cytarabine. The poor prognosis of elderly patients with AML has been improved by the development of stem cell transplantation procedures with reduced intensity conditioning and for patients not suitable for stem cell transplantation, the introduction of less toxic demethylating substances allows a substantial improvement in outcome and quality of life compared to cytoreductive therapy alone. The additional role of targeted therapies in AML is still under investigation. In adult patients with acute lymphoblastic leukemia (ALL), the standard systemic therapy still consists of complex cytotoxic regimens which have been modified from pediatric protocols. Biologically and genetically determined subgroups of ALL patients as well as poor responders, who can be identified by the detection of significant molecular determined residual disease (MRD) after standard therapy, benefit from allogeneic transplantation in first remission. In patients with bcr-abl positive ALL, the implementation of first and second generation tyrosine kinase inhibitors has led to rapidly rising response rates and less toxicity. Patients with relapsed ALL may benefit from new molecular options, e.g. bispecific antibodies. Additionally, improved standardization and supportive care, particularly due to the introduction of modern antimycotic agents, increase the treatment options and improve the prognosis of patients with acute leukemia. The improved diagnostic and therapeutic options for patients with acute leukemia require a complex management. Currently only subgroups of patients benefit from molecular targeted therapeutic strategies. Due to this increasing complexity in the management, patients with acute leukemia should be treated in academic centers and within clinical trials.

Mcl-1 downregulation leads to the heightened sensitivity exhibited by BCR-ABL positive ALL to induction of energy and ER-stress

BCR-ABL positive (+) acute lymphoblastic leukemia (ALL) accounts for ∼30% of cases of ALL. We recently demonstrated that 2-deoxy-d-glucose (2-DG), a dual energy (glycolysis inhibition) and ER-stress (N-linked-glycosylation inhibition) inducer, leads to cell death in ALL via ER-stress/UPR-mediated apoptosis. Among ALL subtypes, BCR-ABL+ ALL cells exhibited the highest sensitivity to 2-DG suggesting BCR-ABL expression may be linked to this increased vulnerability. To confirm the role of BCR-ABL, we constructed a NALM6/BCR-ABL stable cell line and found significant increase in 2-DG-induced apoptosis compared to control. We found that Mcl-1 was downregulated by agents inducing ER-stress and Mcl-1 levels correlated with ALL sensitivity. In addition, we showed that Mcl-1 expression is positively regulated by the MEK/ERK pathway, dependent on BCR-ABL, and further downregulated by combining ER-stressors with TKIs. We determined that energy/ER stressors led to translational repression of Mcl-1 via the AMPK/mTOR and UPR/PERK/eIF2α pathways. Taken together, our data indicate that BCR-ABL+ ALL exhibits heightened sensitivity to induction of energy and ER-stress through inhibition of the MEK/ERK pathway, and translational repression of Mcl-1 expression via AMPK/mTOR and UPR/PERK/eIF2α pathways. This study supports further consideration of strategies combining energy/ER-stress inducers with BCR-ABL TKIs for future clinical translation in BCR-ABL+ ALL patients.

Early MRD response as a prognostic factor in adult patients with acute lymphoblastic leukemia.

To evaluate the prognostic power of minimal residual disease (MRD) monitored by polymerase chain reaction at defined time points during early treatment in adult patients with acute lymphoblastic leukemia (ALL). Seventy-one patients were treated according to the GMALL 07/2003 protocol and evaluated for MRD in bone marrow by specific clonal rearrangements of Ig/TCR in BCR-ABL negative ALL or fusion gene transcript in BCR-ABL positive ALL. Three-year overall survival (OS) was 94% in patients with BCR-ABL negative ALL reaching complete molecular response (CMR) after the first course of chemotherapy (vs. 32% if MRD >10(-4) ; P = 0.001). Patients with CMR prior to the start of consolidation chemotherapy at week 11 had 3-yr OS 82% (vs. 18% if MRD >10(-4) ; P = 0.001). Patients with BCR-ABL positive ALL showed slower MRD dynamics. There was a trend to better OS in patients with ≥ 4 log reduction of BCR-ABL transcript prior to HSCT (92% vs. 50%; P = 0.065). None of the patients with detectable MRD (both BCR-ABL positive and negative) after HSCT survived 3 yr. Early MRD kinetics is an important tool for new prognostication models with direct clinical impact irrespective of standard prognostic factors in patients with BCR-ABL negative ALL.

Molecular genetics of acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL), a clonal expansion of hematopoietic blasts, is a highly heterogeneous disease comprising many entities for which distinct treatment strategies are pursued. Recurrent defects including chromosomal translocations, aneuploidies, and gene-specific alterations generate molecular subgroups of B- and T-ALL with differing clinical courses and distinct responses to therapy. Herein, we review the spectrum of genetic aberrations that promote acute B- and T-ALL, as well as the currently-revealed mechanisms of cell transformation and malignant progression. Although 5-year overall survival of childhood ALL patients has improved to as much as 90% due to progress in chemotherapy and other supporting therapeutic modalities, including allo-HSCT, the prognosis is still poor for the remaining 10% of cases, which consist mainly of MLL-AF4-positive ALL and bcr-abl positive ALL. The prognosis of adults with ALL is not satisfactory and adult ALL remains a challenging disease. The development of novel methodologies, including new molecular therapeutic targets, is also needed to improve the prognosis of ALL.

Progression of molecular genetics in Ph-like acute lymphoblastic leukemia: reports from the 56th American Society of Hematology annual meeting

The event free survival and overall survival rate of acute lymphoblastic leukemia(ALL)have been improved significantly based on the risk stratify diagnosis and treatment. But there are still some patients suffering therapeutic failure and relapse. With the great development of genome sequencing technology, more and more genetic aberrations behind the refractory and relapse ALL have been identified. Ph-like ALL is charactered with gene expression profile similar to that of BCR-ABL1 positive ALL, involving abnormal activation of cytokine receptor and tyrosine kinase. It has been proved that treatment combined with Tyrosine kinase inhibitors(TKIs)can significantly improve the poor prognosis. Ph-like ALL is one of hot topics during the 56th American Society of Hematology(ASH)annual meeting in 2014. Progression in molecular genetics for Ph-like ALL will be introduced together with the author's research experience. Key words: Ph-like acute lymphoblastic leukemia; Tyrosine kinase inhibitors; American Society of Hematology annual meeting

BCR-ABL1-like Acute Lymphoblastic Leukemia Is Associated with IKZF1 and JAK2 Alterations and inferior Outcome in Adults

Background: BCR-ABL1-like (Ph-like) B-precursor acute lymphoblastic leukemia (ALL) displays a gene expression profile closely related to B-precursor ALL with t(9;22)(q34;q11). In addition, Ph-like ALL patients (pts) are characterized by distinct genetic alterations and inferior prognosis in pediatric trials. The purpose of this study was the genetic and clinical characterization of Ph-like ALL in adults.Methods: Affymetrix gene expression profiles (GEP) generated from diagnostic bone marrow samples of 306 adult B-precursor and T-ALL pts (median age 41 years, range 16-84 years) were classified as Ph-like ALL according to published algorithms (Roberts et al., Cancer Cell 2012) and separated from BCR-ABL1-positive and B-other ALL pts (BCR-ABL1-negative; non Ph-like). The incidence and genetic characteristics of the Ph-like subset were analyzed in the overall cohort, whereas clinical and outcome analysis were restricted to B-precursor ALL pts treated within GMALL trials 06/99 and 07/03 (n=107). The median age of this population was 30 (16-64) years. The routine diagnostic work-up included immunophenotyping, fluorescent in situ hybridization (FISH) for BCR-ABL1 and KMT2A (MLL) rearrangements, cytogenetics and molecular analyses of BCR-ABL1 translocations and MLL rearrangements. A subgroup of pts with B-precursor ALL was analyzed for CRLF2 alterations by FISH (n=88) and by RT-PCR for the P2RY8-CRLF2 translocation (n=117). Multiplex ligation-dependent probe amplification (MLPA) for common copy number variations (SALSA MLPA probemix P335-B1) and targeted amplicon sequencing of 131 genes recurrently mutated in ALL were performed in BCR-ABL1 positive (n=30), Ph-like (n=16) and B-other ALL pts (n=23).Results: Of the 306 pts, we classified 26 pts (9%) as Ph-like ALL based on their GEP and the absence of the BCR-ABL1 translocation, corresponding to an incidence of 13% (26/207) in B-precursor ALL and 24% (26/110) among BCR-ABL1-negative B-precursor ALL.Nineteen of 107 B-precursor ALL pts treated within the GMALL trials displayed a Ph-like phenotype. There were no significant differences in baseline characteristics like age, sex, white-cell count, hemoglobin or platelet count and risk group in comparison to the B-other subgroup (n=51). All 19 Ph-like pts showed no MLL rearrangement and 58% belonged to the standard risk group. The complete remission rate after induction was similar for Ph-like and B-other pts (96% vs 100%; p>0.05). At 5 years, the Ph-like ALL subgroup had a lower probability of continuous complete remission (RD: 24% vs 63%; p=0.004) and overall survival (OS: 22% vs 56%; p=0.05) compared to B-other ALL pts. After exclusion of pts with MLL rearrangement from the B-other group (n=11), these differences remained significant (RD: 24% vs 62%; p<0.001; OS: 22% vs 64%; p=0.006).MLPA and amplicon sequencing revealed specific genetic alterations associated with the Ph-like ALL subgroup (Figure 1). All pts with IGH-CRLF2 (n=6) were identified in the Ph-like subgroup, whereas all pts with P2RY8-CRLF2 (n=2) were found in the B-other group (p<0.001 and p>0.05, respectively). Additionally, most pts with high CRLF2 expression clustered in the Ph-like ALL subgroup (13/26, 50% vs 8/79, 10% of B-other; p<0.001). Deletions of IKZF1 were significantly more common in Ph-like ALL (13/16, 81%; p=0.003) and in BCR-ABL1 positive ALL (21/30, 70%; p=0.005) in contrast to B-other ALL (7/21, 30%). Mutations in JAK2 were exclusively found in the Ph-like subgroup (0/53, 0% vs 7/16, 44%; p<0.001). In our data set, FISH for IGH-CRLF2 and sequencing of JAK2 was sufficient to identify Ph-like cases with a sensitivity and specificity of 59% and 100%, respectively.Conclusion: Ph-like ALL in adults is associated with inferior survival in a homogenously treated group of pts. Additionally, molecular analysis revealed distinct genetic alterations identifying this specific ALL subtype. Since gene expression analysis could be difficult to be implemented in routine diagnostics our data suggest, that testing for JAK2 mutations and the IGH-CRLF2 translocation could be options for the diagnosis of the Ph-like subtype. Future treatment strategies should be explored to improve the dismal prognosis for these high risk pts. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Imatinib-Based Chemotherapy for Newly Diagnosed BCR–ABL Positive Acute Lymphoblastic Leukemia: Japan Adult Leukemia Study Group (JALSG) Ph+ALL208 Study

Introduction:The outcome of BCR–ABL positive acute lymphoblastic leukemia (ALL) has drastically improved since the introduction of imatinib. We recently reported the clinical results of the Japan Adult Leukemia Study Group (JALSG) ALL-202 study at the 51th ASH Annual Meeting. Most patients (97.1%) achieved complete remission (CR) and 9% of them relapsed within 100 days after CR. In addition, 60% of patients received allogeneic stem cell transplantation during their first CR, and the 3-year overall survival (OS) rate was 57%. We now present the data of the subsequent JALSG Ph+ALL208 study, where we have modified a part of consolidation therapy to prevent early relapse after achieving CR.Methods:The JALSG Ph+ALL208 study was a phase 2 trial for patients newly diagnosed with BCR–ABL positive ALL. Imatinib at a dose of 600 mg/day was administered from day 8 to day 42 combined with daunorubicine (DNR), cyclophosphamide (CPM), vincristine (VCR) and prednisolone (PSL) for induction therapy. Consolidation therapy comprised course 1 (C1: high-dose methotrexate and high-dose cytarabine with imatinib for 18 days) and course 2 (C2: DNR, CPM, VCR, and PSL with imatinib for 20 days). C1 and C2 were repeated alternately for 4 cycles. After consolidation therapy, allogeneic stem cell transplantation (allo-SCT) was recommended if a suitable stem cell donor was identified. Those ineligible for allo-SCT, due to the lack of a suitable donor and/or comorbidity, received maintenance therapy comprising VCR, PSL and imatinib for 2 years from the date they achieved CR. Seventy patients were enrolled between October 2008 and December 2010. Of these, two patients were excluded because they were diagnosed with chronic myeloid leukemia blast phase. Therefore, 68 patients newly diagnosed with BCR–ABL positive ALL were included in this study. The median age was 49 years (18–64 years) and 41% were >54 years.Results:With this treatment regimen, 65 patients achieved CR (95.6%) and only 1% of them relapsed within 100 days after CR. Finally, 35/40 patients (81%) <55 years-old=“” and=“” 8=“” 28=“” 19=“”>54 years-old were able to receive allo-SCT in their first CR (13 from a sibling donor, 23 from an unrelated bone marrow donor, and 7 from unrelated cord blood). The 3-year OS and disease-free survival (DFS) rates were estimated at 62% and 52%, respectively. Three early deaths occurred during the induction course. One patient (51 years) died of pulmonary bleeding on day 9, another patient (59 years) died of sepsis on day 15, and the third patient (62 years) died of cerebral hemorrhage on day 15. Grade 3 or 4 non-hematologic adverse events including febrile neutropenia and liver dysfunction was reported in 60.3% and 11.8% of the patients, respectively. Twelve patients relapsed after achieving CR with a median time of 307 (64–1053) days. Moreover, 6/43 patients who received allo-SCT relapsed with a median time of 346 (149–602) days. The probability of DFS at 3 years was 72% for patients who underwent allo-SCT in CR compared to only 21% for patients without allo-SCT (p = 0.0004)(Figure.1).Conclusion:We conclude that imatinib-based chemotherapy produced a very high CR rate, thus allowing a high proportion of patients to prepare for allo-SCT, particularly patients 55 years. Moreover, the intensified consolidation therapy reduced the rate of early relapse after induction therapy and resulted in a higher rate of DFS after allo-SCT. [Display omitted] DisclosuresHatta:Bristol Myers Squibb: Honoraria. Miyazaki:Novartis: Honoraria. Ohnishi:Novartis: Honoraria.