Aberrant 5-Hydroxymethylcytosine Levels Correlate With Poor Overall Survival In Acute Myeloid Leukemia

Abstract Background Patients with acute myeloid leukemia (AML) frequently harbor mutations in genes involved in the DNA (hydroxy)methylation pathway (DNMT3A, TET2, IDH1, and IDH2). In addition, changes in DNA methylation have been implicated in the pathogenesis of AML. Recently it was discovered that TET proteins are able to convert 5-methylcytosine into 5-hydroxymethylcytosine (5hmC), which is an important intermediate in the demethylation pathway. In this study, we measured 5-hydroxymethylcytosine levels in AML patients, and correlated these with mutational status and overall survival (OS). Patients and methods Samples from 206 clinically and molecularly well-characterized younger adult AML patients (≤60 years), included in the EORTC/GIMEMA AML-12 06991 clinical trial, were analyzed for mutations in DNMT3A, TET2, IDH1 and IDH2. 5-hydroxymethylcytosine levels were measured using HPLC-MS/MS. Results In healthy control cells, 5hmC levels were confined to a narrow range (1.5 fold difference), whereas in AML cells, a much wider range was detected (15 fold difference). In remission, 5hmC values were normalized to levels comparable to healthy bone marrow and peripheral blood, indicating that the aberrant 5hmC levels at diagnosis are intrinsic to the leukemic cells. Patients with mutations in TET2 and patients with mutations in IDH1/2 had significantly lower levels of 5hmC compared to patients without mutated TET2 and IDH1/2 (both P<.001), whereas mutations in DNMT3A did not influence 5hmC levels. Patients with bi-allelic TET2 inactivation displayed lower 5hmC levels than patients with one affected allele (P=.003). Among the patients that did not harbor TET2 or IDH mutations, still a wide variation in 5hmC levels was observed, and importantly, both low and very high 5hmC levels correlated with inferior OS (P=.02, HR=1.80 and P=.04, HR=1.97, respectively). Multivariate analysis revealed that abnormal levels of 5hmC were independent prognostic indicators for OS. The difference in OS could not be explained by an initial inferior response to therapy, however, the relapse rate was considerably higher in patients with low and very high 5hmC levels compared to patients with intermediate 5hmC. Conclusion Both low and very high levels of 5hmC are markers of poor prognosis in AML, lending further support for testing therapies targeting the DNA hydroxymethylation pathway. Disclosures: No relevant conflicts of interest to declare.

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Acute Myeloid Leukemia with Mutated NPM1 Presenting with Life-Threatening, Either Arterial or Venous, Thromboembolism: a Report of 4 Cases.

Blood ◽

10.1182/blood.v114.22.4135.4135 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4135-4135

Author(s):

Maria Paola Martelli ◽

Lorenzo Brunetti ◽

Luca De Carolis ◽

Elisabetta Agliani ◽

Laura Berchicci ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Venous Thromboembolism ◽

Myeloid Leukemia ◽

Thromboembolic Event ◽

Conflicts Of Interest ◽

The Other ◽

Leukemic Cells ◽

Acute Ischemia ◽

Life Threatening ◽

Acute Myeloid

Abstract Abstract 4135 Acute myeloid leukemia (AML) expressing mutated NPM1 gene and cytoplasmic nucleophosmin (NPMc+ AML) [Falini B et al, NEJM 2005;352:254-266] is a new entity of WHO classification that shows distinctive biological and clinical features. AML with mutated NPM1 usually presents with a high white blood cell count; the bone marrow biopsy is usually markedly hypercellular and leukemic cells frequently show myelomonocytic or monocytic features, with dysplasia and involvement of two or more cell lineages in about 25% of cases. Lack, or low expression, of CD34 in over 90% of cases is the most distinctive immunophenotypic feature of NPM1-mutated AML and is independent of leukemic cell maturation. NPM1 gene mutation without concomitant FLT3-ITD identify a subgroup of AML patients with a favorable prognosis and has been associated with an approximately 50-60% probability of survival at 5 years in younger patients. Here we report 4 out of 41 (10%) patients, admitted at our Hospital in the last year, with new-diagnosed AML with mutated NPM1 presenting with life-threatening thromboembolic (either arterial or venous) events. The main characteristics of these patients are summarized in Table 1. The patients had neither personal nor family history concerning thromboembolism. Hyperleukocytosis was a common feature of the vast majority of NPM1-mutated AML patients at diagnosis. Immunophenotypic analysis did not show a peculiar phenotype in these patients. Table 1 Characteristics of patients with NPM1-mutated AML and thrombosis. Case report no Age Sex (M/F) FAB subtype WBC/mmc Type of thrombosis Site of thrombosis 1 41 F M1 14970 arterial Anterior interventricular branch of left coronary artery 2 56 M M4 93990 arterial external iliac and femoral (right limb) 3 63 M M2 113000 deep venous great saphenous veins (bilateral) 4 73 F M4 190000 deep venous iliac and femoral In two patients (cases 1 and 2), the arterial thromboembolic event (acute myocardial infarction and acute ischemia of right lower limb, respectively) presented about one month before diagnosis of leukemia. In the other 2 patients (cases 3 and 4), deep venous thromboembolism was concomitant with the diagnosis of leukemia. One patient (case 4), who could not initiate chemotherapy for severe concomitant renal failure, died few days after diagnosis. The other patients recovered from the acute event and upon diagnosis of leukemia were promptly treated with standard polychemotherapy which allowed to obtain complete hematological remission associated with complete resolution of the thromboembolic event. The clinical course after chemotherapeutic treatment of the patients outlines the importance and life saving role of early chemotherapy even under adverse circumstances. The pathogenesis of thromboembolic disease in hematological malignancies is complex and multifactorial: tumor cell-derived procoagulant, fibrinolytic or proteolytic factors and inflammatory cytokines affect clotting activation. Other important factors include infectious complications and hyperleukocytosis. However, large vessel thrombosis is a very rare clinical presentation. Our report of severe thromboembolic events at presentation in AML with mutated NPM1 suggests some still unidentified biological features of this leukemia which we are currently investigating. Disclosures: No relevant conflicts of interest to declare.

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Immunophenotyping Features in Acute Myeloid Leukemia (AML) with NPM1+ and/or FLT3+

Blood ◽

10.1182/blood.v118.21.4908.4908 ◽

2011 ◽

Vol 118 (21) ◽

pp. 4908-4908

Author(s):

Pervin Topcuoglu ◽

Klara Dalva ◽

Sinem Civriz Bozdag ◽

Onder Arslan ◽

Muhit Ozcan ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Leukemic Cells ◽

Aberrant Expression ◽

Hla Dr ◽

Cd36 Expression ◽

Cd34 Cells ◽

Cd56 Expression ◽

Acute Myeloid

Abstract Abstract 4908 Immunophenotyping Features in Acute Myeloid Leukemia (AML) with NPM1 and/or FLT-3 Positive Pervin Topçuoglu, Klara Dalva, Sinem Civriz Bozdag, Önder Arslan, Muhit Özcan, Osman Ýlhan, Hamdi Akan, Meral Beksaç, Günhan Gürman Aim: We aimed to evaluate immunophenotypical (IP) features in AML pts with NPM1+ and/or FLT3+ except on acute promyelocytic leukemia. Patients&Method: Between Nov 2009 and Feb 2011, we retrospectively analyzed IP features by flow cytometry (FCM) in 51 pts (46M;17F) with new diagnosed AML. Median age was 46 years (range: 14–71 ys). The mutations of NMP1 and FLT-3 TKD&ITD were determined by the methods of RQ-PCR or RFLP, respectively in the samples of bone marrow (n=31) or periheral blood (n=20) at the diagnosis. Antigenic expression of leukemic cells was analyzed by four-color FCM (FITC, PE, PerCP&APC) based by Nomdedeu et al researh (Leuk res 2011; 35:163) (Table-1). Results: We detected NMP1+ mutation in 16 patients. Of these, three were associated with mutations of FLT3-ITD (n=2) or -TKD (n=1). Twelve patients had FLT3+ (9 ITD or 3 TKD). More than half of the patients without any mutation were CD15+/CD34+/HLA-DR+ and 11.5% for CD34 negative. Similarly, the patients with FLT-3 positive were mostly CD34+ as the pts w/o any mutations. Contrary, most of the pts with NMP1+ were CD34 negative (56.3%) (Table 1). When evaluated the complete IP in leukemic cells, the expression of CD123 was significantly marked in the patients with NPM1+ and/or FLT3+ than those w/o mutations (p=0.008). While the co-expression of CD7 and CD117 was found in 67% of the pts w/o any mutations, 30% of the pts with NMP1 and/or FLT-3 ITD (p=0.01). CD56 expression was detected in more pts with NMP1+ than those with FLT-3+ (40% vs 8%, p=0.04). Besides, CD36 expression was positive in the all pts with FLT3-ITD than TKD+ (p=0.005). More intensive CD33 expression was seen in NMP1+ pts. The expression of CD64 was similar in all three mutations. Conclusion: Though NMP1 mutation was associated more CD34+ cells, more FLT3+ pts had CD34 positivity. The expression of CD123 was especially associated with the mutations. Aberrant expression of CD56 was in more pts with NPM1+, but CD36 for FLT3-ITD. These data might be a step for a study aiming to show a correlation between the type of mutations combined with IP features of leukemic cells and clinical characteristics or disease course of AML pts. Disclosures: No relevant conflicts of interest to declare.

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DNMT3A mutations Predict for Inferior Outcome in NPM1-Wildtype and Molecular Unfavorable Cytogenetically-Normal Acute Myeloid Leukemia: A Study of the German-Austrian AMLSG

Blood ◽

10.1182/blood.v118.21.415.415 ◽

2011 ◽

Vol 118 (21) ◽

pp. 415-415 ◽

Cited By ~ 1

Author(s):

Verena I. Gaidzik ◽

Richard F. Schlenk ◽

Peter Paschka ◽

Anja Stölzle ◽

Andrea Corbacioglu ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Negative Impact ◽

Epigenetic Modification ◽

Methylation Status ◽

Prognostic Impact ◽

Sequencing Analysis ◽

Mutational Status ◽

Acute Myeloid

Abstract Abstract 415 Background: Alteration of DNA methylation, a hallmark of epigenetic modification, is currently discussed as one important pathomechanism in leukemogenesis. Using a next-generation sequencing approach, a frameshift mutation of the gene encoding the DNA methyltransferase (DNMT3A) in an acute myeloid leukemia (AML) case was identified. DNMT3A catalyses the addition of a methyl group to the cytosine residue of CpG dinucleotides, thereby affecting promoter methylation status and gene expression. Subsequent sequencing analysis in an independent cohort of 288 AML patients (pts) revealed DNMT3A mutations (DNMT3Amut) in 22% of the pts; mutations were associated with intermediate-risk cytogenetics and poor outcome. Aims: To evaluate frequency and clinical impact of DNMT3Amut in pts with AML aged 18 to 61 years who were treated within AMLSG treatment trials AML HD98A (Schlenk et al., J Clin Oncol 2010;28:4642–8) and AMLSG 07–04 (NCT00151242). Methods: DNMT3A mutation analysis was performed in 1218 AML (HD98A, n=685; AMLSG 07–04, n=533; de novo AML, n=1102; s-AML, n=45; t-AML, n=69) using a DNA-based PCR assay for all coding exons (1 to 23) followed by direct sequencing. The median follow-up was 5.06 years. Results: DNMT3A mut were found with an overall frequency of 19.6% (239/1218); 189 mutations were located in the MTase domain clustering at amino acid R882 (79%). All but one mutation were heterozygous; only 4 cases had two mutations. DNMT3A sequence alterations included 17 frameshift, 4 nonsense, and 222 missense mutations. DNMT3A mut pts were significantly older (P=.01), more frequently females (P=.001), had higher white blood cell and platelet counts (both P<.0001), and higher bone marrow blasts percentage (P=.001). DNMT3Amut were associated with cytogenetically-normal AML (CN-AML, P<.0001), while DNMT3Amut were rare in favorable and adverse-risk karyotypes (P<.0001). Correlations with other molecular markers (NPM1, CEBPA, FLT3, IDH1/2, TET2, ASXL1) revealed a significant association with NPM1 (P<.0001), FLT3-ITD (P<.0001), and IDH1/2 (IDH1R132, P<.0001; IDH2R140, P=.0003; IDH2R172, P=.03) mutations, while co-occurrence of CEBPA (P=.02) and ASXL1 (P=.02) mutations was less frequent. DNMT3A mutational status did not impact complete remission (CR) rate, event-free (EFS) and relapse-free survival (RFS), neither in the whole cohort (P=.09, P=.98, P=.11; respectively) nor in the subgroup of CN-AML (P=.39, P=.79, P=.19, respectively). DNMT3Amut had a negative impact on overall survival (OS) in trend in the whole cohort (P=.07) and significantly in CN-AML (P=.02). In multivariable analyses, DNMT3Amut were in trend associated with a negative prognostic impact on OS (hazard ratio, 1.24; P=.06). In addition, we performed subgroup analyses according to (1) the NPM1 mutational status, and (2) the molecular risk groups of CN-AML (as defined by the European LeukemiaNet classification). DNMT3Amut did not impact OS in NPM1-mutated patients in the whole cohort as well as in CN-AML (P=.34; P=.22; respectively), while in NPM1-wildtype patients DNMT3Amut were associated with inferior OS in both, the whole cohort and in CN-AML (P=.001; P=.005; respectively). In molecular unfavorable CN-AML (NPM1-wildtype with or without FLT3-ITD, NPM1-mutated with FLT3-ITD, CEBPA-wildtype), DNMT3Amut were significantly associated with worse OS (P=.002) compared with DNMT3A-wildtype pts, even outweighing FLT3-ITD as an unfavorable prognostic marker. There was no effect of DNMT3Amut in molecular favorable-risk CN-AML. Conclusions: DNMT3A mutations are confirmed as frequent genetic aberrations in AML, associated with normal karyotype, NPM1, FLT3-ITD, and IDH1/2 mutations. DNMT3Amut predicts for inferior outcome in molecularly-defined subsets of AML, that is, NPM1-wildtype AML and molecular unfavorable CN-AML. As a single marker, DNMT3Amut only had a moderate effect on outcome. Disclosures: No relevant conflicts of interest to declare.

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Lack of Association of Mutations in IDH1, IDH2, DNMT3A with Outcome in Older Patients with Acute Myeloid Leukemia Treated with Hypomethylating Agents (± Histone Deacetylase Inhibitors).

Blood ◽

10.1182/blood.v120.21.2483.2483 ◽

2012 ◽

Vol 120 (21) ◽

pp. 2483-2483

Author(s):

Farhad Ravandi ◽

Keyur P. Patel ◽

Rajyalakshmi Luthra ◽

Sherry A. Pierce ◽

Gautam Borthakur ◽

...

Keyword(s):

Valproic Acid ◽

Overall Survival ◽

Acute Myeloid Leukemia ◽

Histone Deacetylase ◽

Older Patients ◽

Myeloid Leukemia ◽

Research Funding ◽

Hypomethylating Agents ◽

Idh Mutations ◽

Acute Myeloid

Abstract Abstract 2483 Background: Mutations of several genes believed to be important in the methylation apparatus of the cell have been recently described in patients with acute myeloid leukemia (AML) but their presence has not been correlated with a worse or better outcome using hypomethylating agents. Methods: We evaluated the association of mutations in IDH1, IDH2, DNMT3A, and EZH2 with the outcome [complete response (CR) rate, event free survival (EFS) and overall survival (OS)] among patients older than 60 with AML (≥ 20% blasts) treated with hypomethylating agents as their first line of treatment. TET2 mutations were not evaluated due to lack of available material. Results: Among the 68 patients (median age 72 years; range, 60 – 83) with available data, 11 patients (16%) had IDH1 or IDH2 mutations (mutually exclusive) and 10 patients (15%) had DNMT3A mutations with 5 patients (7%) having both IDH and DNMT3A mutations. Cytogenetics was diploid in 19 (28%), abnormal chromosome 5/7 and/or complex in 27 (40%), trisomy 8 in 5 (7%), miscellaneous in 14 (21%), and insufficient in 3 (4%). Presence of IDH mutations was associated with a diploid karyotype and the presence of NPM1 mutations (p=.03 and p=.02, respectively) but not with FLT3- ITD or RAS mutations (present in 7 and 4 patients, respectively). DNMT3A mutations were not associated with any specific karyotype or with the presence of NPM1, FLT3-ITD, or RAS mutations. None of the 68 patients had EZH2 mutations. All patients were treated with hypomethylating agents [decitabine in 39 (57%) and 5-azacytidine in 29 (43%)] with 42 patients (62%) receiving concomitant histone deacetylase inhibitor therapy (SAHA or valproic acid). Overall, 17 patients (25%) achieved CR; the presence of IDH or DNMT3A mutations or both was not associated with achievement of CR. With a median duration of follow-up of 60 months, the median EFS is 3.3 months (range, 0.25 – 3.75 months) and the median overall survival is 6 months (range, 0.25 – 90.5 months). Presence of IDH mutations was not associated with an impact on EFS (p=.29) or OS (p=.14). Similarly, DNMT3A mutations were not associated with an effect on EFS (p=.21) or OS (p=.58). The presence of both IDH and DNMT3A mutations was also not associated with a better or worse response, EFS, or OS as compared with patients with neither mutation. Conclusion: We were not able to detect an association between presence of IDH1/2 and DNMT3A mutations and outcome in this elderly population of patients with AML treated with epigenetic modulators. Disclosures: Ravandi: Johnson and Johnson: Honoraria; Celgene: Research Funding. Off Label Use: Use of decitabine, 5-azacytidine, SAHA, and valproic acid in the treatment of older patients with AML. Garcia-Manero:Celgene: Research Funding. Cortes:Celgene: Research Funding; Eisai: Research Funding.

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Activity of the Hypoxia-Activated Prodrug, TH-302, in Human Acute Myeloid Leukemia Models

Blood ◽

10.1182/blood.v120.21.3611.3611 ◽

2012 ◽

Vol 120 (21) ◽

pp. 3611-3611

Author(s):

Scott Portwood ◽

Deepika Lal ◽

Yung-Chun Hsu ◽

Rodrigo Vargas ◽

Meir Wetzler ◽

...

Keyword(s):

Overall Survival ◽

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Flow Cytometric Analysis ◽

Chemotherapeutic Agents ◽

Scid Mice ◽

Hypoxic Conditions ◽

Acute Myeloid

Abstract Abstract 3611 Recent evidence has demonstrated the bone marrow (BM) microenvironment, the principal site of acute myeloid leukemia (AML) initiation and expansion, is characterized by intrinsically low oxygen tension. Theoretically, such microenvironmental changes may lead to the selective outgrowth of AML clones which are “better adapted” to survive within a severely hypoxic microenvironment and/or may confer resistance to chemotherapeutic agents, similar to solid tumor cells. We report here that human AML cells (HL60, ML-2) cultured under chronic hypoxic conditions mimicking the marrow microenvironment (1% O2, 72 hours) exhibited reduced sensitivity to cytarabine-induced apoptosis as compared with normoxic cells, as determined by flow cytometric analysis, western blot analysis, and cell viability assays. Similar results were noted in primary AML samples treated with cytarabine under normoxic and hypoxic conditions in colony formation assays (n=3 samples, p=0.01). In order to improve upon chemotherapy outcomes, we investigated the effects of TH-302, a hypoxia-activated bromo-isophosphoramidate mustard prodrug, which is currently undergoing clinical trial evaluation in multiple tumor types. Treatment of AML cell lines (HL60, HEL) and primary AML samples with TH-302 (at doses ranging from 0.1– 5 mM, p values ranging from <0.05–0.0001) resulted in dose- and hypoxic-dependent inhibition of AML proliferation and apoptosis. In vivo TH-302 treatment significantly decreased disease burden, as measured by total animal bioluminescence, and prolonged overall survival in two systemic human AML xenograft models (HEL-luciferase, HL60-luciferase) (Figure 1). Immunohistochemical studies demonstrated that TH-302 treatment reduced numbers of hypoxic (pimonidazole-positive) cells within the leukemic marrow microenvironment. Because prior data in animal models has shown that AML progression within the marrow is associated with expansion of hypoxic BM areas, we examined the effects of TH-302 treatment on systemic AML growth when initiated early (prior to AML inoculation) or late (several days following AML engraftment) in the disease process. TH-302 was equally effective at both time points. Although anti-vascular therapy has been shown to enhance tumor hypoxia in other cancer types, we noted no synergistic or additive in vivo effects when TH-302 therapy was combined with sorafenib, an inhibitor of vascular endothelial growth factor receptors (VEGFR), in our models. TH-302 therapy administered for two weeks in non-leukemic and leukemia-engrafted mice was not associated with hematologic toxicities. In summary, our results demonstrate the anti-leukemic activity of TH-302 in preclinical AML models and suggest that the efficacy of this and other drugs for AML therapy may be uniquely affected by the BM microenvironment. Further clinical development of TH-302 and other hypoxia-targeted drugs for AML therapy are warranted. Based on our data, higher TH-302 doses and/or chronic drug administration may be needed for optimal in vivo anti-leukemic activity. Figure 1. Effects of TH-302 treatment on systemic AML growth and overall survival in HL60-luciferase engrafted SCID mice. Figure 1. Effects of TH-302 treatment on systemic AML growth and overall survival in HL60-luciferase engrafted SCID mice. Disclosures: No relevant conflicts of interest to declare.

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Unraveling The Leukemic Nature Of hMICL and CD123 Expressing Cells In Acute Myeloid Leukemia

Blood ◽

10.1182/blood.v122.21.2626.2626 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2626-2626 ◽

Cited By ~ 2

Author(s):

Line Nederby ◽

Peter Hokland ◽

Gordon Brown ◽

Maria Hansen ◽

Charlotte Guldborg Nyvold ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Capillary Electrophoresis ◽

Myeloid Leukemia ◽

Mononuclear Cells ◽

Conflicts Of Interest ◽

Leukemic Cells ◽

Fragment Analysis ◽

Marker Combination ◽

Allelic Burden ◽

Acute Myeloid

Abstract Flow cytometry constitutes a cornerstone in the diagnosis and follow up of acute myeloid leukemia (AML) and it is based on the identification of leukemia-associated immunophenotypes (LAIPs). We have recently demonstrated that the C-type lectin hMICL in combination with CD123 constitute a highly stable and reliable LAIP marker combination at diagnosis and relapse. In addition, we have shown that an hMICL/CD123-based assay is an effective tool for the monitoration of minimal residual disease (MRD) in AML. To what extent hMICL/CD123 marking identifies early leukemic cells is, however, not established. We hypothesized that this could be addressed by studying molecular aberrations in leukemic cell subsets according to their expression of hMICL and CD123. Employing cell sorting and mutational analyses, we here establish the leukemic origin of hMICL and CD123 expressing cell populations. Analyzing diagnostic AML samples with homozygous FLT3-ITD aberrations allowed for verification of pure malignant clones. Five patients with FLT3-ITD allelic burden of >50% (range 77-93%, median 85%) as measured by DNA fragment analysis by capillary electrophoresis on mononuclear cells (MNC) were identified in our local database of 600 cases. We found that 5/5 patients displayed a normal karyotype and carried NPM1 mutations (NPM1 allelic burden 42-48%, median 46%). In contrast, mutations in FLT3-D835, IDH1-R132, c-KIT-D816V or indel mutations in CEBPA and WT-1 exon 7 were absent. From samples of cryopreserved mononuclear cells (bone marrow (n=4) and peripheral blood (n=1)), CD45low/SSClow blast cell subsets with the following immunophenotypes were sorted by FACS: CD34+/hMICL+/CD123+, CD34+/hMICL+/CD123-, CD34+/hMICL-/CD123+, and CD34+/hMICL-/CD123-. In one case of CD34 negative AML the sorted subsets were CD34-/hMICL+/CD123+, CD34-/hMICL+/CD123-, CD34-/hMICL-/CD123+, and CD34-/hMICL-/CD123-. Sorted cell subsets were analyzed for FLT3-ITD and NPM1 mutations using fragment analysis by capillary electrophoresis. The results of the fragment analyses are tabulated in the table below. In all cases the hMICL and CD123 expressing subsets of interest closely approximated 100% FLT3-ITD allelic burden. In contrast, hMICL-/CD123- cells approximated only a 50% FLT3-ITD allelic burden. Of note, an extended search in our AML database, revealed only 9 of 600 patients to have an FLT3-ITD allelic burden >50% (range 52-94%, median 81%) hence indicating a state of either homo- or hemizygosity. Interestingly, with the exception of one case carrying a chromosome 13 duplication, each of these 9 patients also harbored a mutation in the NPM1 gene as the only other known aberration. In conclusion using AML patients with high FLT3-ITD allelic burdens we have been able to show that blasts expressing hMICL and/or CD123 at diagnosis are indeed malignant thus further substantiating the use of these antigens in AML MRD detection. Additionally, a direct relationship between NPM1 and FLT3-ITD homo-/hemizygosity may be suggested in the evolution of the malignant clone.Phenotype of sorted cell subsetNumber of patientsFLT3-ITD allelic burden (%) Min-max (median)NPM1 allelic burden (%) Min-max (median)MNC577-93 (85)42-48 (46)CD45low/SSClow/CD34+/hMICL+/CD123+495-100 (98)48-50 (49)CD45low/SSClow/CD34+/hMICL+/CD123-1*9248CD45low/SSClow/CD34+/hMICL-/CD123+497-100 (99)47-51 (48.5)CD45low/SSClow/CD34+/hMICL-/CD123-436-68 (47)16-38 (25)CD45low/SSClow/CD34-/hMICL+/CD123+110046CD45low/SSClow/CD34-/hMICL+/CD123-19448CD45low/SSClow/CD34-/hMICL-/CD123+110047CD45low/SSClow/CD34-/hMICL-/CD123-17735*Subset only present in one of four patients Disclosures: No relevant conflicts of interest to declare.

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A Novel Path for ATRA Differentiation Therapy in Acute Myeloid Leukemia with Isocitrate Dehydrogenase Mutations

Blood ◽

10.1182/blood.v124.21.3727.3727 ◽

2014 ◽

Vol 124 (21) ◽

pp. 3727-3727

Author(s):

Jean-Emmanuel Sarry ◽

Helena Boutzen ◽

Christian Récher

Keyword(s):

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Negative Regulator ◽

Granulocytic Differentiation ◽

Induced Differentiation ◽

Idh1 R132h ◽

Recurrent Mutations ◽

Idh Mutations ◽

Acute Myeloid

Abstract Acute myeloid leukemia (AML) is characterized by accumulation of malignant blasts with impaired differentiation programs due to recurrent mutations, among which IDH mutations occur in 15% of AML patients. These mutations lead to a block in erythroid commitment while they may also bias hematopoietic differentiation to myeloid lineage. Interestingly, Lyn tyrosine kinase is required for erythroid differentiation and we have observed a reduction of Lyn expression in the presence of IDH1-R132H mutation. It is also a negative regulator of ATRA-induced granulocytic differentiation. Accordingly, we hypothesized that IDH mutations may sensitize AML cells to ATRA-induced differentiation. Here, we report that clinically achievable doses of ATRA are sufficient to trigger differentiation specifically on AML cell lines, primary patient samples and xenograft mice models carrying IDH1 mutation as observed by an increase in CD11b expression, granulocytic enzyme activity and morphologic changes in May-Grunwald-Giemsa staining. We also showed that ATRA-induced terminal granulocytic differentiation increases apoptosis while decreases proliferation and colony formation specifically in IDH1 mutant cells. Moreover, inhibition of IDH1-R132H activity reduced ATRA-sensitivity while increasing expression of IDH mutation correlated with highest ATRA sensitivity. Furthermore, treatment with a cell-permeable form of the oncometabolite specifically produced by the mutant (eg. 2-HydroxyGlutarate) sensitized AML cells to ATRA-induced differentiation. Finally, because ATRA-induced differentiation triggers a transient increase of Lyn activation, its association with Lyn inhibitors synergistically increased ATRA-induced differentiation of IDH mutant blasts. In summary, our results showed that IDH mutations by producing 2-HG sensitized leukemic blasts to ATRA and that this synergizes with Lyn inhibition. Since 2HG concentration reaches millimolar in AML patient serum and is 100-fold higher in IDH mutated patients than in non-mutated ones, we would predict a strong efficacy and specificity of ATRA. Furthermore, as IDH mutations are systematically conserved at relapse, this therapeutic strategy might be promising to achieve a long-term remission specifically for this AML patient subgroup. Disclosures No relevant conflicts of interest to declare.

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Treatment Acute Myeloid Leukemia Using Cytoreductive Chemotherapy Cytarabine (Ara-C) Followed Azacitidine (AZA) Maintenance: A Real Life Single Center Experience

Blood ◽

10.1182/blood.v128.22.5204.5204 ◽

2016 ◽

Vol 128 (22) ◽

pp. 5204-5204

Author(s):

Rosa Greco ◽

Annamaria Petrungaro ◽

Anna Grazia Recchia ◽

Laura De Stefano ◽

Sabrina Bossio ◽

...

Keyword(s):

Bone Marrow ◽

Acute Myeloid Leukemia ◽

Median Duration ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Real Life ◽

Response To Therapy ◽

Significant Activity ◽

Intensive Chemotherapy ◽

Acute Myeloid

Abstract Background: Older patients (pts) with acute myeloid leukemia (AML) have a particularly dismal outcome, because of adverse features of AML in the elderly and frailty. The median duration of complete remission (CR) last less than 1 year. The optimal management of older AML pts in daily clinical practice has not been determined. Regular treatment options include best support care, low dose cytarabine (Ara-c) and intensive chemotherapy (anthracycline combined with ara-c). Recently, the DNA methyltransferase inhibitor Azacitidine (AZA) has demonstrated significant activity and favorable tolerability in AML pts also showing a survival advantage. Materials and Methods: Between May 2013 and July 2016, at our institution, 19 pts with a diagnosis of AML (13 males and 7 females) were judged to be ineligible for intensive chemotherapy due to age or comorbidities. They received a 5-day regimen of cytoreductive chemotherapy with ara-c at a dosage of 100 mg\mq\day i.v. continuous infusion. On the sixth day, on termination of Ara-c infusion, all pts had ≤30% bone marrow blasts. Therefore, AZA was administered at a dosage of 75 mg\mq\day subcutaneously for 7 days, continuing the therapy every 28 days. The median age of pts was 75 years (range, 49 to 79 years), with 17 pts (89%) aged over 65 years. Six pts (32%) had poor molecular and cytogenetic risks markers, and six other pts (32%) had either antecedent myelodisplastic/myeloproliferative diseases or therapy related AML. The response to therapy according to the AML IWG criteria was assessed by bone marrow aspiration immediately after Ara-c infusion, after one AZA cycle and every 6 months thereafter. Baseline pts characteristics are summarized in Table 1. Results: The median number of administered AZA cycles was 6 (range, 1-25 cycles). Fifty eight percent (11/19) of pts received ≥6 AZA clycles. The median overall survival was 6 months (range, 1-26 months). According to AML IWG criteria, 8 pts (42%) achieved CR after Ara-c and a single AZA cycle. Of these, 5 pts (62%) are currently alive in CR, with median duration of response of 7 months (range: 5-12 months), while 3 pts (38%) died after 4, 12, and 22 months after diagnosis. One pt (5%) achieved a partial response (PR) after one AZA cycle, maintaining at present the same response after 3 months of therapy. Other 8 pts (42%) obtained stable disease (SD). Of these, 3 pts (37%) are currently in SD after 2, 8 and 10 months of therapy, while 5 pts (64%) died within a median of 5 months (range: 2 - 18 months) after AML diagnosis. Finally 1 pt (5%) was refractory dying after 2 months of diagnosis, and another pt (5%) died after first AZA cycle for sepsis. Fever and infections were the most common non-hematologic toxic events after Ara-c chemotherapy and first AZA cycle (17/19 pts, 90%). While subsequent AZA cycles were well tolerated. Conclusion: We suggest that the use of Ara-c-AZA combination is feasible in elderly AML pts. However, the relatively small number of pts studied and short follow up preclude definitive conclusion. The study is still accruing patients. Disclosures No relevant conflicts of interest to declare.

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ETO2-GLIS2 Controls Differentiation Arrest and Self-Renewal through Aberrant Enhancers Regulation in Pediatric Leukemia

Blood ◽

10.1182/blood.v128.22.572.572 ◽

2016 ◽

Vol 128 (22) ◽

pp. 572-572

Author(s):

Cecile Thirant ◽

Cecile K Lopez ◽

Cathy Ignacimouttou ◽

M'Boyba Diop ◽

Lou Le Mouël ◽

...

Keyword(s):

Acute Myeloid Leukemia ◽

Myeloid Leukemia ◽

Conflicts Of Interest ◽

Genetic Alterations ◽

Leukemic Cells ◽

Hematopoietic Progenitors ◽

Pediatric Leukemia ◽

Self Renewal ◽

Megakaryocytic Differentiation ◽

Acute Myeloid

Abstract Deregulated gene expression due to genetic alterations, such as gene fusions affecting transcription and/or epigenetic factors is the hallmark of acute myeloid leukemia and the basis for the differentiation block of hematopoietic progenitors. Acute megakaryoblastic leukemia (AMKL) is a subtype of poor prognosis acute myeloid leukemia (AML) affecting primarily young children. Recently, the ETO2-GLIS2 fusion has been identified in 20-30% of de novo AMKL and associated with the worst prognosis in this subtype of AML. To characterize the transformation induced by ETO2-GLIS2, we first defined the consequences of ETO2-GLIS2 expression on hematopoietic progenitors and the contribution of ETO2 and GLIS2 on differentiation and self-renewal. Using methylcellulose replating assays and phenotype characterization, we show that the GLIS2 moiety drives the megakaryocytic phenotype whereas both the ETO2 and GLIS2 moieties are required for maintaining self-renewal. Global expression profiling and comparison to patients' signature consistently identify ETO2-GLIS2-mediated deregulation of major transcriptional regulators of hematopoiesis and leukemogenesis, including overexpression of the ERG oncogene. ChIP-seq analysis reveals that ETO2-GLIS2 is recruited at normal ETO2 complexes sites and also at GLIS2-specific targets through binding via GLIS2 DNA-binding domain. We demonstrate that ETO2-GLIS2 fusion localize at half of H3K27Ac-dense enhancers, so called super-enhancers, to control transcription of associated genes. We show that interaction of ETO2-GLIS2 with ETO2 complexes is an essential node for the transcriptional control by the fusion at enhancer elements. Indeed, ETO2-GLIS2 dimerizes and interacts with endogenous ETO2 via its NHR2 domains. An NHR2 peptide-interference strategy inhibits oligomerization, reverses the transcriptional activation at enhancers, promotes megakaryocytic differentiation and abrogates human AMKL cells maintenance in vivo. Finally, upregulation of ERG by ETO2-GLIS2 further strengthen enhancers formation as ERG is co-recruited generating a feed forward loop at these elements and its knockdown or genetic inactivation downregulates expression of ETO2-GLIS2 targets required for leukemic cells survival. We propose that the megakaryocytic differentiation arrest and self-renewal controlled by ETO2-GLIS2 results from an imbalance in the expression of master transcription factors imposed by aberrant chromatin structures at enhancers that may be disrupted by targeting the NHR2 interface. Disclosures No relevant conflicts of interest to declare.

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Prognostic Impact of the Interaction between DNMT3A mutation and Internal Tandem Duplication of the FLT3 Gene (FLT3-ITD) in Patients with De Novo Mutated NPM1 (NPM1mut) acute Myeloid Leukemia

Blood ◽

10.1182/blood-2018-99-115337 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1492-1492

Author(s):

Guadalupe Oñate ◽

Ana Garrido ◽

Jordi Esteve ◽

Rosa Coll ◽

Montserrat Arnan Sangerman ◽

...

Keyword(s):

Overall Survival ◽

Acute Myeloid Leukemia ◽

Complete Remission ◽

Myeloid Leukemia ◽

De Novo ◽

Prognostic Impact ◽

Intermediate Risk ◽

Mutational Status ◽

De Novo Aml ◽

Acute Myeloid

Abstract Introduction The association of NPM1mut and FLT3-ITD in de novo acute myeloid leukemia (AML) with intermediate-risk cytogenetics has different prognostic impact depending on the FLT3 allelic burden. Previous studies published by our cooperative group showed that patients with de novo AML of intermediate-risk cytogenetics with NPM1mut and FLT3-ITD low ratio (<0.5, FLT3low) at diagnosis presented an overall survival and relapse rate similar to those with NPM1mut and FLT3wt. Therefore, in the CETLAM-2012 protocol, patients with FLT3low NPM1mut AML are not considered for allogenic hematopoietic stem cell transplant (allo-HSCT) in first complete remission (CR1). Recent studies suggest that the co-occurrence of DNMT3A mutation in FLT3-ITD NPM1mut AML patients confers a worse prognosis regardless of FLT3-ITD ratio. We analysed our data to determine whether these findings were confirmed in our cohort, specifically in the low FLT3-ITD ratio patients, since this could have therapeutic implications. Methods and patients A total of 163 patients with de novo AML, intermediate-risk cytogenetics and NPM1mut were analysed (median age 53 years (18-72); male:female 72:91 (0.79)). Eighty patients (49%) harboured an FLT3-ITD, with a high allelic ratio in 42 of 76 patients with available ITD/wt ratio (55%). They were included in the AML-2003 (n=49) and AML-2012 (n=114) CETLAM protocols. Proportion of patients undergoing alloHSCT in CR1 is detailed in table 1. Bone marrow samples from diagnosis were studied for DNMT3A mutations as previously described. The definition of complete remission (CR), overall survival (OS), leukemia-free survival (LFS) and risk of relapse (RR) followed recommended ELN criteria. The Kaplan-Meier method was used to estimate the distribution of LFS and OS, for RR cumulative incidence was used. Results Out of the 163 patients with AML of intermediate risk cytogenetics and NPM1mut, 78 presented DNMT3A mutations (48%). Of these, 62 (79%) presented mutations in codon R882 or corresponded to DNA insertions/deletions while 16 (21%) harboured missense mutations. Presence of DNMT3A mutation did not associate with FLT3-ITD (ITD/85 DNMT3Awt vs ITD/78 DNMT3Amut, p=0.394). In the entire cohort, 5-year OS, LFS and RR were 58±4.5%, 59±4.6% and 27±13.9%. FLT3-ITD ratio confirmed its prognostic impact when analysing FLT3wt (n=83) vs FLT3low (n=34) vs FLT3high (n=42) patients (5-year OS of 68±6% vs 62±8.7% vs 37±8.6%; p=0.002; and 5-year RR of 18±9.4% vs 27±16.1% vs 41±23.2%; p=0.023). On the contrary, DNMT3Amut did not exert any effect on overall outcome (5-yr OS DNMT3Awt vs DNMT3Amut 61±6.2% vs 55±6.2%; p=0.234) When DNTM3A mutational status was considered, the impact of FLT3-ITD on outcome was mitigated in wild-type DNMT3A population. Thus, we found that DNMT3Awt patients presented no statistical differences in OS according to FLT3 mutational status or ratio: FLT3wt (n=46) vs FLT3-ITD (n=39) was 67±8.5% vs 57±8.2%; p=0.122, whereas FLT3wt (n=46) vs FLT3low (n=18) vs. FLT3high (n=19) was 67±8.5% vs. 66±11.5% vs 46±11.8%; p=0.088 (image 1A).This was also seen in relation to LFS and RR according to FLT3 ratio: 5-yr LFS of FLT3wt vs FLT3low vs FLT3high was 72±7.9% vs 61±12.6% vs 51±13.4%; p=0.244 and 5-year RR of the same groups: 19±8.8% vs 26±12.5% vs 27±21.9%; p=0.724 (image 2A). In the DNMT3Amut group, patients with FLT3-ITD (n=41) presented shorter OS than those with FLT3wt (n=37) with an OS of 37±10.7% vs 69±7.8%; p=0.028. When FLT3 ratio was considered, FLT3wt (n=37) vs FLT3low (n=16) vs FLT3high (n=23) showed an OS of 69±7.8% vs. 58±13.2% vs 27±13.1%; p=0.038 (image 1B). Similar results were seen in LFS according to FLT3 ratio (FLT3wt (n=29) vs FLT3low (n=16) vs FLT3high (n=20) 71±8.6% vs 53±12.9% vs 18±13.8%; p=0.012). Finally, we observed significant differences in the 5-year RR when considering DNMT3Amut patients in relation to FLT3 ratio (FLT3wt vs FLT3low vs FLT3high 18±10.6% vs 27±20% vs 54±28.8%; p=0.021)(image 2B). Conclusions In this study, patients with NPM1mut and FLT3-ITDlow presented a similar outcome to patients with NPM1mut and FLT3wt regardless of DNMT3A mutational status. These results support the modification of alloHCST policy in CR1 in CETLAM-2012, which do not consider alloHSCT for patients with FLT3low. On the other hand, concurrence of DNMT3A mutation may have an added negative effect in patients with NPM1mut and FLT3-ITDhigh, which should be further confirmed in larger studies. Disclosures No relevant conflicts of interest to declare.

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