Favorable AML Research Articles

Validation of the ELN 2017 Classification for AML with Intermediate Risk Cytogenetics with or without NPM1 -Mutations and High or Low Ratio FLT3-ITD s

IntroductionNucleophosmin 1-mutations (NPM1) and internal tandem duplications in the FMS-like tyrosine kinase 3 receptor gene (FLT3-ITDs) are the most frequently detected molecular abnormalities in patients with AML and are used for risk assessment and stratification of post-remission therapy. In the 2017 ELN recommendations (Döhner et al, Blood 2017) FLT3-ITD mutations are grouped according to the ratio of the mutant (mt) to wild type (wt) alleles into low ratio (LR) and high allelic ratio (HR) mutations using a cut-off of 0.5. AML with intermediate risk (IR) cytogenetic abnormalities and NPM1 -mutant FLT3- wt AML is grouped together with NPM1 -mutant and LR FLT3-ITD as favorable risk AML, only NPM1 -wt HR FLT3-ITD AML is considered adverse risk. Since validation studies have not been published so far for the 2017 ELN recommendations, we analyzed survival of patients with IR cytogenetic abnormalities who were treated in randomized controlled trials on intensive induction chemotherapy of the Study Alliance Leukemia (SAL) in the past two decades.MethodsWe performed a retrospective study on all patients who had received intensive induction chemotherapy for newly diagnosed AML within randomized SAL trials with available data on ELN 2017 classification. All molecular studies were performed centrally in one laboratory. Cox regression analyses were fitted with baseline risk factors including genetic markers for the full analysis set. Interaction tests were used to determine the impact of gene-gene interactions. Extended Cox regression models with a time-dependent covariate modeling the time of allogeneic hematopoietic stem cell transplantation (alloHCT) were used to study the role of alloHCT for patients who had reached first complete remission (CR1).ResultsIn total, data on 1610 IR-patients was evaluable. The median age at first diagnosis of AML was 55 years (range, 18 to 87 years), both sexes were equally represented and 72% of patients had normal karyotype AML. Eighty-three percent of patients had de novo AML, 12% secondary AML and 3% therapy-related AML. The median follow-up was 81 months (interquartile range, 63 to 103 months). Numbers of patients in the respective genetic subgroups defined by the 2017 ELN classifications and 5-year overall survival (5-yr-OS) probabilities from diagnosis were as follows (see also Figure 1): 418 patients with FLT3-ITD wt NPM1 mt AML with 50% 5-yr-OS and 119 patients with LR FLT3-ITD with NPM1 mt AML with 41% 5-yr-OS were classed together as favorable AML, 741 patients with FLT3-ITD wt NPM1 wt AML with 27% 5-yr-OS, 170 patients with HR FLT3-ITD with NPM1 mt AML with 31% 5-yr-OS, and 70 patients with LR FLT3-ITD with NPM1 wt AML also with 31% 5-yr-OS were classed as intermediate risk AML and finally 92 patients with HR FLT3-ITD with NPM1 wt AML with 20% 5-yr-OS were classed as adverse risk AML. In any combination NPM1 mutations had a protective effect. Interaction tests indicated that the combination of an NPM1 -mutation and LR FLT3-ITD increased the risk of mortality compared to the single mutations (Wald-test for interaction, p=0.08).When alloHCT in first complete remission was analyzed in an extended Cox regression analysis as time-dependent covariate, the impact differed among patients assigned to the three risk groups defined by the 2017 ELN recommendations: Results indicated that alloHCT had no impact on overall survival in patients with favorable AML HR 1.0 (95%-CI, 0.8 - 1.2), but a beneficial impact in patients with intermediate risk AML HR 0.8 (95%-CI 0.7 - 0.9) or high risk AML HR 0.7 (95%-CI 0.5 - 1.0).ConclusionsThe risk classification of the 2017 ELN recommendations according to NPM1 and FLT3-ITD genotypes was validated in this large retrospective analysis including data from 1610 patients with newly diagnosed AML with intermediate risk cytogenetic abnormalities or normal karyotype. The time-dependent analysis of alloHCT indicated that patients with favorable AML should not receive alloHCT as post-remission therapy in CR1, whereas patients with intermediate risk or high risk AML would benefit from alloHCT in CR1. [Display omitted] DisclosuresSchetelig:Sanofi Aventis: Consultancy, Research Funding; Roche: Honoraria; Abbvie: Honoraria; Janssen: Consultancy, Honoraria. Rollig:Janssen: Research Funding; Bayer: Research Funding. Kayser:TEVA: Honoraria; Novartis: Honoraria, Speakers Bureau. Stoelzel:medac: Other: Travel support. Bug:Amgen: Honoraria; Janssen: Other: Travel Funding; Novartis: Honoraria, Research Funding; Celgene: Honoraria, Other: Travel funding; Astellas: Other: Travel Funding; Jazz Pharmaceuticals: Other: Travel Funding. Mayer:Novartis: Research Funding; Eisai: Research Funding. Thiede:Novartis: Consultancy, Speakers Bureau; Roche: Consultancy; Agendix: Employment; Bayer: Consultancy, Speakers Bureau.

Implantation of Patient-Derived Acute Leukemia Cells into the Hematopoietic Niche of Immunocompromised Mice Favors Faithful Recapitulation of the Disseminated Growth of Human Leukemia

The aim of this study was to determine the influence of the engraftment site on the tumor biology and drug sensitivity of a panel of hematological patient derived xenografts (PDX). PDX cells (3x10e6 cells/mouse) were injected intratibially (i.t.), intrasplenically (i.s.) or subcutaneously (s.c.) into NOG (NOD/Shi-scid/IL-2Rγnull) mice. Leukemic cell engraftment was determined by flow cytometry (FC) in bone marrow (BM), peripheral blood (PB) and spleen during the course and at the end of the experiment. Overall survival (OS) served as an additional read-out. In nine models, sensitivity towards cytarabine (Cy) was evaluated across the different implantation sites. Up to now our group has established 26 PDX of acute leukemia (23 AML, one ALL, two APL) covering a broad range of the different genetic subtypes: amongst other molecular alterations models carrying PML-RARA or AML1-ETO fusion proteins are included in the collection. 24/26 lines engrafted when injected i.t., 17/22 developed tumors after i.s. implantation and 16/19 established tumors post s.c. injection of T cell depleted PB or BM of patients. Hence, for the majority of the models the engraftment capacity per se was not dependent on the injection site. Yet, some models could exclusively be propagated in a specific setting: one AML model, grew solely i.t. or i.s., whereas another AML and one APL could be propagated only when injected s.c.. The implantation site did influence tumor growth behavior: Mean OS ranged from 161.3 (±22.3) days for i.t. to 93.1 (±13.1) days for s.c. propagation. I.s. transplanted mice had to be sacrificed after 137.6 (±25.2) days. The differences in mean OS between the three settings were not statically significant (one way ANOVA). Nevertheless, the OS times within single models differed significantly depending on the implantation technique (p ranging from < 0.005 - 0.017, Log-rank (Mantel-Cox) test). The dissemination pattern of individual lines was as well affected by the injection site. In general, infiltration of the investigated hematopoietic organs was significantly higher when cells were engrafted i.t. or i.s as compared to the s.c. approach (p< 0.0001, one way ANOVA). The mean BM (i.t.: 58.1 ± 8.1%; i.s.: 51.3 ± 13.4%; s.c.: < 0.01%), spleen (i.t.: 40.4 ± 8.8%; i.s.: 52 ± 11.5%; s.c.: < 0.01%) and PB (i.t.: 36.6 ± 8.1%; i.s.: 36.4 ± 12.0 %; s.c.: 10.4 ± 7.2 %) infiltration rate across all 26 models was similar in the i.t. and the i.s. setting but considerably higher than in the s.c approach. Significant differences could be detected between individual models depicting characteristic engraftment patterns independent of the injection site (p ranging from < 0.003 - 0.02, one way ANOVA). The expression pattern of the six investigated surface markers (CD45, CD3, CD34, CD33, CD38 & HLA-ABC) was not influenced by the application route. Every model depicted its distinct expression pattern similar to the expression pattern of the donor sample. Of note, the expression pattern was stable across different passages in the murine host. Cy was highly active in five AML and one ALL model: OS was significantly prolonged in the s.c. as well as in the disseminated setting (p ranging from < 0.001 - 0.003, Log-rank (Mantel-Cox) test). Three other AML models depicted a less pronounced sensitivity towards Cy (p ranging from < 0.005 - 0.007, Log-rank (Mantel-Cox) test) both growing s.c. or i.t.. Thus, drug sensitivity was not influenced by the injection site of the leukemic cells. To the best of our knowledge, this is the first time that such a thorough side-by-side comparison was performed in acute leukemia PDX models. Taken together, the application route has a major impact on the tumor biology of the PDX model: i.t. and i.s but not s.c. implantation induced a disseminated growth pattern mimicking consistently the human disease. Up to now, implanting leukemic cells i.t. led to the highest engraftment rate (92%) within the panel of established AML PDX models, indicating the importance of the hematopoietic niche as a supportive tumor microenvironment. Therefore, the establishment of favorable genetic AML subtypes should be preferably done by i.t. implantation. Nevertheless, the consistent expression of surface markers as well as sensitivity towards Cy independent of the implantation site, justifies the use of s.c. implanted AML PDX for screening approaches in an early stage of the drug development process. DisclosuresSchueler:Charles River Research Services Germany GmbH: Employment. Lenhard:Charles River Research Services Germany GmbH: Employment. Klingner:Charles River Research Services Germany GmbH: Employment. Oswald:Charles River Research Services Germany GmbH: Employment.

Is Hydroxyurea Deleterious in Patients with ELN Favorable AML and WBC Inferior to 50.109/L?

Oral hydroxyurea (HU) is often prescribed in hyperleukocytic acute myeloid leukemia (HL-AML). A retrospective study showed that a pre-treatment with HU prior to intensive chemotherapy could improve early survival of patients with HL-AML (Mamez AC et al. Leuk Lymph 2016). We have also shown that a HU prephase before chemotherapy was independently associated with improved overall survival (OS) (aHR=0.44 [0.26-0.76], p=.003), event-free survival (EFS) (aHR=0.51 [0.31-0.85], p=.009) and disease-free survival (DFS) (aHR=0.38 [0.22-0.68], p=.001) in AML with WBC > 50.109/L (Récher C et al. Blood 2016 128:1636). HU is also given in patients with a moderate leukocytosis in the interval before consultation or referral and prior to the induction. In vitro data suggested that a pretreatment of AML cells with HU could enhance the cytotoxic activity of intercalating agents in part through synchronization of AML cells in S phase (Ritch PS et al. Cancer Res 1981 et Minford J et al. Cancer Res 1984). In this retrospective study, we sought to determine whether a HU prephase, could impact response to chemotherapy and outcome in non HL-AML.We included 646 AML patients with initial WBC <50.109/L treated with induction chemotherapy in our center between 2004 and 2015. Median follow-up was 54.1 months.91 patients were treated with HU before induction chemotherapy. Delay from AML diagnosis to HU initiation was 1 day (interquartile range [IQR], 0-5.5). Median duration of HU treatment was 5 days (IQR, 3-14.5). Compared to the 555 patients that did not receive HU, HU treated-patients were older (median: 63.3 vs 59.1 years, p=.001), had a poorer ECOG performance status (ECOG 2-4: 36.5 vs 15.7%, p<.0001), more secondary diseases (30.8 vs 22.7% p=.0941), higher WBC (median: 24.7 vs 4.2.109/L, p<.0001), more frequently ELN 2010 intermediate-1 (35.2 vs 20.4%, p=.0046), more FLT3 -ITD mutations (30.8 vs 10.6%, p<.0001), more leukostasis symptoms (5.5 vs 0.4%, p=.0008), higher creatinine level (91 vs 80 µM, p<.0001), higher lactate dehydrogenase level (818 vs 558 UI/L, p<.0001). They were also more frequently admitted in intensive care unit (ICU) (24.2 vs 9.1%, p<.0001) and suffered from more grade 3-4 hemorrhagic complications (8.0 vs 2.9%, p=.0288) during induction phase.HU treatment was associated with decreased complete remission (CR) (71.4 vs 80.2%, p=.0576) and increased early death rate (ED) (14.3 vs 7.0%, p=.0183). It was also associated with decreased EFS (9.0 vs 14.7, p=.001), DFS (10.3 vs 23 months, p=.006) and OS (11.7 vs 26.6, p<0.001), in univariate analyses. In multivariate analyses including age, secondary status, ECOG, ELN classification, WBC, ICU admission, leukostasis and allogeneic stem-cell transplantation in first CR, HU treatment had no significant impact on ED (HR=1.07, p=.868) and DFS (HR=1.03, p=.875). However, there was a significant interaction between HU treatment and ELN 2010 classification for CR, OS and EFS. Indeed, HU treatment had a significant impact only in ELN 2010 favorable subgroup (CR: HR=0.12, p=.012; OS: HR=3.35, p=.004; EFS: HR=2.19, p=.055). Contrarily, in other ELN 2010 subgroups (intermediate-1 and -2, adverse and unknown), HU treatment had no significant impact on OS and EFS.In this retrospective study, we uncovered a potential deleterious effect of HU used before intensive chemotherapy in AML patients with WBC < 50.109/L and ELN 2010 favorable risk. Molecular reasons underlying this unexpected result are unknown. The impact of HU prior to induction chemotherapy should be carefully assessed in a multicenter setting. In the absence of leukostasis symptoms or rapid increase in WBC, HU treatment before induction should be avoided in this subgroup of patients. DisclosuresRecher:Novartis, Celgene, Jazz, Sunesis, Amgen: Consultancy; Celgene, Sunesis, Amgen, Novartis: Research Funding.

63 - Decreased Overall Survival in 2017 ELN Favorable AML Group with Positive DNA Methylation Regulatory Genes Mutations

63 - Decreased Overall Survival in 2017 ELN Favorable AML Group with Positive DNA Methylation Regulatory Genes Mutations

AML-291: MRD Level After Induction Therapy in NPM1-Mutated Patients Identifies Those at High Risk of Relapse and Defines Indications for HSCT

Context Patients with NPM1 AML mutation are included in ELN favorable or intermediate genetic risk categories, although a proportion of these patients will relapse. Thus, it is necessary to identify negative prognostic factors for patientss with NPM1 and to evaluate if ASCT could overcome them. Objective To determine the clinical significance of post-remission MRD level NPM1 mutation and correlation with treatment outcome in AML patients. Design Twenty-seven patients with NPM1mut in CR were included in the study. All patients had WT1 overexpression. Additional genetic abnormalities were revealed in 12 patients ([hyperexpression of BAALC (n=4), IDH1/2 (n=4), FLT3ITD (n=8), DNMT3AR882C (n=1), ASXL1(n=1), RUNX1(n=1), aberrant karyotype (n=4)]. Monitoring of minimal residual disease was studied after induction («7+3) and consolidation courses («HiDAC»). Thirteen patients underwent HSCT. Median follow-up was 12 months (2.2–109 months). Results CIR (median 7.25 months vs not reached), RFS (median 7.25 months vs not reached) and OS (median 7.25 vs 41.80 months) were shorter in patients with NPM1mut reduction after an induction course less than 3.85 log (specificities 81.8%, sensitivities 100%) (p=0.001, p=0.0036, and p=0.05, respectively). Patients with NPM1+FLT3- status had similar results with this cut-off (median RFS 9.6 months vs not reached, p=0.037). Cutoff levels of NPM1mut 4.2 log (specificities 83.3%, sensitivities 83.3%) after the first consolidation course separated the cohort into two prognostic groups (14 and 13 patients) as well: median CIR 7.25 vs 41.80 months (p=0.02) and median OS 13 months vs not reached, p=0.05, respectively). MRD status after consolidation therapy in comparison to the MRD status after induction therapy has improved only in two patients but with relapse in 17.7 months and 9.7 months. HSCT improved CIR and OS in the group of patients with cut-off less than 3. 85 log (p=0.016, p=0.03). In the multivariate model with MRD cut-off, age, genetic abnormalities, FLT3 status, and WBC only post-induction cut-off level NPM1 were independent prognostic factors for RFS (HR:0.07; 95% CI: 0,006–0.955; p=0.04). Conclusions NPM1mut-positive patients have adverse prognosis if the post-induction reduction of expression of these genes is less than 3.85 log. This cut-off separated ELN favorable NPM1mut AML patients. Unfavorable prognosis of MRD cut-off-positive patients during AML treatment could be overcome with HSCT in the first CR.

Rural but Not Urban AML Exhibit Cytogenetic and Molecular Characteristics of Therapy-Related AML

Background:There are few established risk factors for AML. Benzene, radiation, prior chemotherapy treatments for cancer, and cigarette smoking have been causally linked with AML. Few studies have shown that incidence rates are highest in the agricultural region and it has been hypothesized that farming and its related exposures (e.g., pesticides) may account for this increased risk. Nonetheless, there are no do data regarding clinical, cytogenetic and molecular differences between rural and urban area. The primary objective of this study is to look for cytogenetic features of rural patients. Secondary objectives are to search for clinical and molecular characteristics.Patients and methods: We conducted a retrospective analysis of 521 AML patients treated in 2 french institutions (Amiens University Hospital and Lille University Hospital) between 2008 and 2013. Patients with therapy related AML have been excluded. Patient demographics as well as clinical, hematological, cytogenetics and molecular data were collected from the Nord-pas de Calais and Picardie observatory. European Leukemia Net (ELN) classification was used for cytogenetics prognosis. We geocoded addresses using the geographic information system of the french National institute of statistics and economics (INSEE, http://www.insee.fr). According to the INSEE criteria, a location of residence was defined as rural for a city of population under 2,000 inhabitants without a contiguous built area of more than 200 m. Moreover, the population was divided into quartiles according to the percentage of farm in local companies.Results: In our population 120/521 patients (23%) lived in a rural area and 401/521 (77%) in an urban area. Sex ratio (1.6 vs 1.2, p=0.2) and median age at diagnosis (64 vs 61 years, p=0.05) were similar.There was no difference in complete blood count (hemoglobin, platelets, leukocytes and circulating blasts levels) as well as bone marrow blasts percentage, type of AML (de novo vs post MDS or MPN) and WHO classification at diagnosis between the two groups.Concerning cytogenetic anomalies, proportion of favorable and intermediate AML were similar between the two groups. However, there are more patients with unfavorable cytogenetics in rural area (41% vs 28%, p=0.04). Moreover, we observed more 11q23 anomalies in the rural patients group (22% vs 9%, p=0.04). Concerning molecular anomalies, rural patients seem to have less FLT3-ITD positivity (11% vs 19%, p=0.2), and CEBPAmutation (2% vs 7% p= 0.07) without significance. Overall survival was similar between the two groups.Same results have been obtained when we compared patients depending on the proportion of farm in their area (table 1.) with more MLL anomalies (p=0.03) and unfavorable cytogenetics (p=0.005).Conclusions:Our results showed that rural AML might present specific features. These AML would present more like therapy-related AML with more 11q23 anomalies and more unfavorable cytogenetics feature.Abstract 2353. Table 1Characteristics of AML according to the proportion of farm in the areaProportion of farmp%≤ 0.8n= 1440.8<% ≤ 3.9n=1223.9<% ≤ 11.3n=128%> 11.3n=130Age, median (range)63 (61-65)62 (60-66)61 (56-64)63 (61-66)0.34Sex ratio (M/F)1.251.281.321.430.9Type of AML, secondary (%)28/136 (20)18/109 (17)15/116 (13)24/124 (19)0.4White blood cells, 109/L6.8 (4.5-10.8)7.8 (4.6-14.2)7.9 (5.6-14.4)4.5 (3.4-7)0.08Bone marrow blasts, %53 (49-60)59 (46-66)54 (43-62)47 (38-56)0.2WHO classification, (%)AML with reccurent genetic abnomalities32/122 (30)26/103 (25)26/104 (27)21/107 (20)0.7AML with myelodysplasia related changes49/122 (40)33/103 (32)33/104 (33)46/107 (43)0.8AML NOS42/122 (34)43/103 (42)39/104 (37)39/107 (36)0.6Cytogenetics, (%)Favorable35/100 (35)27/93 (29)29/95 (31)22/92 (24)0.4Intermediate40/100 (40)44/92 (48)32/95 (34)33/92 (36)0.2Unfavorable25/100 (25)21/92 (23)33/94 (35)37/92 (40)0.03MLL rearrangement, (%)3/78 (4)3/63 (5)14/79 (18)14/82 (17)0.005Molecular biology, (%)FLT3 ITD18/105 (17)18/92 (19)21/93 (22)7/77 (9)0.22NPM mutation31/93 (33)22/89 (25)24/89 (27)13/75 (17)0.3CEBPA mutation7/94 (7)3/86 (3)5/83 (6)4/73 (5)0.6 DisclosuresNo relevant conflicts of interest to declare.

Genetic Patterns of Relapsed AML Differ Significantly from First Manifestation and Are Dependent on Cytogenetic Risk Groups at Diagnosis: Results in 175 Patients with Paired Samples

Introduction: Genetic changes between diagnosis and relapse in AML have not been analyzed comprehensively yet. Especially in the favorable risk group (acute promyelocytic leukemia (APL) with PML-RARA, and core binding factor (CBF) leukemias with CBFB-MYH11 or RUNX1-RUNX1T1) data is scarce.Aim: To investigate genetic patterns in AML with favorable risk cytogenetics at diagnosis and at relapse in comparison to all other AML subtypes.Patients and Methods: We investigated 175 AML patients diagnosed by cytomorphology, immunophenotyping and cytogenetics following WHO criteria both at diagnosis and at relapse (350 samples). Cytogenetic risk stratification followed MRC as favorable, intermediate, and adverse (Grimwade, Blood 2010). 30 patients were diagnosed as APL or CBF leukemia (favorable), while 122 patients were intermediate, and 23 adverse risk. Data on molecular mutations was available for subsets of patients including ASXL1, CEBPA, DNMT3A, EZH2, FLT3-ITD, FLT3-TKD, KIT, IDH1, IDH2, MLL-PTD, NPM1, NRAS, KRAS, RUNX1, TET2, TP53, and WT1. Gene mutations were analyzed by Sanger sequencing, NGS, melting curve analysis, or gene scan. Cytogenetics was available for all 350 samples.Results: Changes in mutational and cytogenetic patterns of APL and CBF leukemias: 28 relapse samples revealed in total 22 gene mutations in 12 genes, with a median number of 0.8 mutations per patient. 7 patients (25%) showed no mutation, 20 (71%) showed 1 mutation, and 1 (4%) had 2 mutations. Most frequently FLT3-ITD was found (n=5), followed by mutations in KIT (n=3), EZH2, FLT3-TKD, NRAS, TET2 (for each n=2), and ASXL1, DNMT3A, IDH1, KRAS, TP53, and WT1(for each n=1). In 17/20 patients with molecular mutations identified either at relapse or primary diagnosis both samples were analyzed for the specific mutation. 22 mutations were present in this subset. Of these 10 (46%) mutations were already detected at primary diagnosis and thus remained stable, while 3/22 (14%) mutations were gained and 9/22 (41%) were lost at relapse. Including patients with no mutation revealed that 13/24 (54%) patients showed an unchanged mutation pattern while 11/24 (46%) gained or lost mutations. The karyotype was stable in 16/30 (53%) cases with favorable cytogenetics, while 14/30 (47%) showed cytogenetic changes: although the main cytogenetic aberration remained unchanged in all relapse samples the latter patients showed either clonal evolution (n=11), clonal regression (n=2) or both (n=1).Changes in mutational and cytogenetic patterns of AML with intermediate risk cytogenetics: In the intermediate risk group (97/122 patients (80%) had normal karyotype) the cytogenetic changes were slightly less frequent with 44/122 (36%). Interestingly, in this group 3 patients occurred with a totally different karyotype at relapse compared to primary diagnosis. In 2 cases, however, the molecular markers remained stable, while in 1 patient also the mutation pattern changed completely. Therefore, the latter one might be a t-AML, while the other two are most likely relapses. The molecular mutation patterns were unstable in this subgroup with 56/94 (60%) patients showing mutational gains as well as losses.Changes in mutational and cytogenetic patterns of AML with adverse cytogenetics: 11/23 patients (48%) showed cytogenetic changes. Also in this group 1 patient might have acquired a t-AML rather than a relapse as suggested by complete changes in cytogenetics and molecular markers. Only 5/18 (26%) showed changes in the mutational pattern at all. Of notice, while in favorable AML mutation patterns changed at relapse more by losses than by gains of mutations, in the intermediate and adverse groups gains of mutations were more frequent. The latter two groups had more mutations already at primary diagnosis and acquired additional mutations mostly in FLT3-ITD but also in the whole spectrum of analyzed genes, particularly in prognostically unfavorable genes such as TP53, ASXL1, RUNX1, DNMT3A, or WT1.Conclusions: 1) In AML with favorable cytogenetics the defining aberrations persist at relapse but changes in karyotype and mutational pattern occur in 47% and 46% of cases. 2) AML with intermediate risk cytogenetics is characterized by instability predominately on the molecular level. 3) AML with adverse cytogenetics shows only few changes in the molecular profile but high karyotype instability. DisclosuresMeggendorfer:MLL Munich Leukemia Laboratory: Employment. Alpermann:MLL Munich Leukemia Laboratory: Employment. Perglerová:MLL2 s.r.o.: Employment. Kern:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Schnittger:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership. Haferlach:MLL Munich Leukemia Laboratory: Employment, Equity Ownership.

Core-binding factor acute myeloid leukemia in first relapse: a retrospective study from the French AML Intergroup

AbstractAlthough core-binding factor-acute myeloid leukemia (CBF-AML) (t[8;21] or inv[16]/t[16;16]) represents a favorable cytogenetic AML subgroup, 30% to 40% of these patients relapse after standard intensive chemotherapy. The encouraging results of gemtuzumab ozogamicin (GO) in newly diagnosed AML, and particularly in CBF-AML, incited us to retrospectively investigate the impact of GO-based salvage in these patients. We retrospectively analyzed the outcome of 145 patients with CBF-AML (59 t[8;21], 86 inv[16]/t[16;16]) in first relapse. As salvage, 48 patients received GO-based chemotherapy and 97 patients received conventional chemotherapy. Median age was 43 years (range, 16-76). Median first complete remission duration was 12.1 months (range, 2.1-93.6). Overall, second complete remission (CR2) rate was 88%. With a median follow-up from relapse of 3.5 years, the estimated 5-year disease-free survival (DFS) was 50% and 5-year overall survival (OS) was 51%. Older age and shorter first complete remission duration was associated with a shorter OS. Patients treated with GO had similar CR2 rate but significantly higher 5-year DFS (68% vs 42%; P = .05) and OS (65% vs 44%; P = .02). In multivariate analysis, GO salvage was still associated with a significant benefit in DFS and OS. In the 78 patients who received allogeneic hematopoietic stem cell transplantation in CR2, GO before transplant significantly improved posttransplant DFS and OS without excess of treatment-related mortality.

Outcome of older patients with acute myeloid leukemia in first relapse

To provide data for future drug evaluation, we analyzed the outcome of 393 patients aged 50 years or older (median, 64 years) with AML in first relapse after treatment in recent ALFA trials. Salvage options were retrospectively classified as follows: best supportive care (BSC), low-dose cytarabine (LDAC), gemtuzumab ozogamicin (GO), intensive chemotherapy (ICT), or ICT combined with GO. Second complete remission (CR2) rate was 31% and median post-relapse survival was 6.8 months (0, 17, 42.5, 53, and 80% and 3.2, 5.6, 8.9, 9, and 19.8 months in BSC, LDAC, GO, ICT, and ICT + GO subsets, respectively). Age, performance status, WBC, CR1 duration, and favorable AML karyotype, but not other cytogenetic or molecular features, influenced post-relapse outcome. Multivariate adjustment and propensity score matching showed that intensive salvage (ICT/ICT+GO/GO versus LDAC/BSC) was associated with longer post-relapse survival, at least in patients with CR1 duration ≥12 months (P = 0.001 and 0.0005, respectively). Of interest, GO appeared to be as effective as standard ICT, and ICT + GO combination more effective than standard ICT. In conclusion, older patients with CR1 duration ≥12 months appeared to benefit from intensive salvage and results observed with GO-containing salvage suggest that GO combination studies should be actively pursued in this setting.

Prognostic relevance of FLT3-TKD mutations in AML: the combination matters—an analysis of 3082 patients

We characterized the mutational status of the FLT3 tyrosine kinase domain (FLT3-TLD) in 3082 patients with newly diagnosed AML. FLT3-TKD mutations were detected in 147 of 3082 (4.8%) patients. Similar to the FLT3 juxtamembrane domain mutations (FLT3-LM), there was a high correlation of FLT3-TKD mutations with normal karyotype (88 of 1472; 6.0%). FLT3-TKD mutations were most frequent in the AML FAB subtypes M5b (15 of 114; 13.2%), M3v (6 of 51; 11.8%), and M4 (39 of 484; 8.1%). Similar to FLT3-LM, the FLT3-TKD mutations show elevated peripheral leukocytes compared with FLT3wt AML. FLT3-TKD had a high incidence in cases with NPM1 mutations (23 of 262; 8.8%), CEBPA mutations (6 of 76; 7.9%), and NRAS mutations (6 of 78; 7.7%). FLT3-TKD in combination with FLT3-LM (17 of 594 patients; 2.9%) and KITD816 (1 of 44; 2.3%) was rare. Unlike the FLT3-LM, which are associated with inferior survival, prognosis was not influenced by FLT3-TKD in the total cohort of 1720 cases, where follow-up data were available (97 FLT3-TKD; 1623 FLT3-WT). In t(15;17)/PML-RARA with FLT3-TKD mutations, in FLT3-LM/TKD double-mutated, and in MLL-PTD/TKD double-mutated cases prognosis was unfavorably influenced by FLT3-TKD mutations. In contrast, we found an additional favorable impact of FLT3-TKD on EFS in prognostically favorable AML with NPM1- or CEBPA mutations.

Prognosis of Acute Myeloid Leukemia with Translocation (8;21): A Survey of 142 Cases Investigated in the JALSG AML97 Study.

Background: Translocation (8;21) is one of the most common structural aberrations found in AMLand good response rates and a better DFS have been described in pts possessing it. Especially, the DFS rate may exceed 60–70% in younger pts given repetitive courses of HDAra-C. However, it was recently reported that a subtype of AML with t(8;21) showed a poor prognosis and this case also had the KIT mutation. As a result, we retrospectively analyzed the prognosis of AML pts with t(8;21) prospectively enrolled in the JALSG AML97 study.Patients and Methods: Between 1997 and 2001, JALSG AML97 enrolled 809 pts previously untreated for AML and pts with M3 were excluded. From the 789 eligible pts, we selected the subjects with t(8;21) for this study. Induction therapy consisted of cytarabine and idarubicin. All CR pts were randomized to receive either four courses of standard dose consolidation therapy without maintenance therapy or three courses of standard dose consolidation with 6 courses of maintenance therapy. HDAra-C was not administered in the JALSG AML97 study. Peripheral blood and bone marrow smears and karyotypes were reevaluated by the central review committees. Any patients who underwent SCT were censored at the date of SCT. The Kaplan-Meier method was used to estimate OS and DFS. For comparisons of OS or DFS, the log rank test was used.Result: Cytogenetic studies were performed in 783 patients (99.2%) and only 15 studies resulted in failure. One hundred forty-two (18.5%) of those pts showed t(8;21). The median age was 43 yrs (15–64). The male: female ratio was 95: 47. The distribution of FAB types was as follows: AMLM2, 130; M4, 6; M1, 5; and M5, 1. A total of 69 (48.6%) pts had a sole t(8;21), 46 (32.4%) had a loss of a sex chromosome, and 27 (19.0%) had other cytogenetic abnormalities. The CR rate was 90.0%. Thirty-two pts underwent two courses of induction therapy. The early death (< one month) rate was 1.4% (2/142). Only a high WBC count (>=10x109/L) was found to be a marginally significant prognostic factor (p=0.0517). The estimated OS rate at 5yrs was 53.6%, and the DFS of the CR pts was 41.2%. We found no relationship between OS or DFS and the following factors: age, gender, karyotypic abnormality, performance status, the percentage of MPO positive blasts, the presence or absence of Auer rods, the platelet count, the number of induction therapies for CR and the type of postremisson therapy. However, two factors, the WBC count and the percentage of blasts in bone marrow were found to be strongly predictive factors for the outcome. For the pts with a WBC count >=10x109/L, the DFS rate at 5yrs was 30.8%, while for the pts with less than 10x109/L, it was 48.8% (p=0.0215). For the pts with blast >=50% and less than 50%, the DFS rates at 5yrs were 32.2% and 56.7% (p=0.0087), respectively. According to these two factors, a poor risk group (N=30, 21.0%) was thus identified. They had a WBC count >=10x109/L and blast >=50%. The DFS rate at 5yrs was only 22.3 % in the poor risk group while that of the other pts was 48.9% (P=0.0003).Conclusion: This study confirmed that all AML pts with t(8;21) shows a high response rate and a good prognosis, thus indicating that this favorable AML group includes a poor risk group which can be identified based on the WBC count and the blast percent in the bone marrow.