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Calcitonin receptor-like (CALCRL) is a G-protein-coupled neuropeptide receptor involved in the regulation of blood pressure, angiogenesis, cell proliferation, and apoptosis, and is currently emerging as a novel target for the treatment of migraine. This study characterizes the role of CALCRL in acute myeloid leukemia (AML). We analyzed CALCRL expression in collectively more than 1500 well-characterized AML patients from five international cohorts (AMLCG, HOVON, TCGA, Leucegene, and UKM) and evaluated associations with survival. In the AMLCG analytic cohort, increasing transcript levels of CALCRL were associated with decreasing complete remission rates (71.5%, 53.7%, 49.6% for low, intermediate, high CALCRL expression), 5-year overall (43.1%, 26.2%, 7.1%), and event-free survival (29.9%, 15.8%, 4.7%) (all P < 0.001). CALCRL levels remained associated with all endpoints on multivariable regression analyses. The prognostic impact was confirmed in all validation sets. Genes highly expressed in CALCRLhigh AML were significantly enriched in leukemic stem cell signatures and CALCRL levels were positively linked to the engraftment capacity of primary patient samples in immunocompromised mice. CRISPR- Cas9-mediated knockout of CALCRL significantly impaired colony formation in human myeloid leukemia cell lines. Overall, our study demonstrates that CALCRL predicts outcome beyond existing risk factors and is a potential therapeutic target in AML.

About 20-25% of patients with Acute Myeloid Leukemia (AML) have primary drug resistant disease and fail to achieve complete remission after induction therapy. These patients have an extremely poor prognosis and cannot reliably be identified prior to therapy with current methods. The aim of this work was to develop a predictive tool that can identify therapy resistant patients with high accuracy at the time of diagnosis. We used two independent Affymetrix gene expression (GE) data sets and standard molecular and clinical variables to develop a predictive score for response to cytarabine/anthracycline-based induction chemotherapy. The "training set 1" consisted of 407 adult AML patients enrolled in the AMLCG-1999 trial (GSE37642). Training set 2 included 449 adults treated in various HOVON trials (GSE6891). GE-based classifiers for primary treatment resistance were developed in training set 1 using a penalized logistic regression approach (Lasso). A cut off with a specificity of 90% was predefined in training set 1. Training set 2 was used to select the best classifier. The predictive score and cut off were then validated in a third, fully independent data set, comprising 260 patients enrolled in AMLCG-1999 and 2008 trials studied by RNA sequencing. Additionally, targeted amplicon sequencing data for 68 recurrently mutated genes in AML was available for training set 1 and the validation set. The final classifier (Predictive score 29 MRC - PS29MRC) consisted of 29 gene expression values and the cytogenetic risk group (defined according to the United Kingdom Medical Research Council (MRC) classification) and was calculated as a weighted sum of Lasso coefficients and predictor values. PS29MRC was a highly significant predictor of resistant disease in the validation set with an odds ratio of 2.32 (p=1.53x10-8, AUC: 0.75). We tested the signature in a multivariable model including all variables with univariate p-value Since we aimed to develop a clinically useful score, we categorized PS29MRC to distinguish between patients who have a high probability of refractory disease and those who are likely to benefit from induction therapy (complete remission or complete remission with incomplete hematologic recovery). By applying the predefined cut off, we were able to reach a specificity of 90% and sensitivity of 46% in the validation set (OR: 7.83; p=6.06x10-9). The accuracy of PS29MRC was 77%. In the multivariable model the categorized classifier was highly significant (OR: 4.45; p=0.00040) and only age and TP53 mutations were left as significant variables again. Within the cytogenetic subgroups favorable (n=14; refractory: n=0; responders: n=13), intermediate (n=189; refractory: n=43; responders: n=136) and adverse (n=49; refractory: n=29; responders: n=15) the classifier showed an accuracy of 100%, 78% and 66%, respectively. Furthermore, the classifier predicted survival and was able to unravel the intermediate MRC subgroup (Figure). Additionally, genes included in our predictive signature seem to be involved in AML pathogenesis and potentially actively contribute to mechanisms responsible for primary therapeutic resistance. For example MIR-155HG, an already known parameter of inferior outcome in AML, contributed significantly to PS29MRC. There are currently ongoing trials with the novel inhibitor Pevonedistat that aim to modulate this target in AML. In summary we were able to develop a predictive risk classifier summarizing 29 gene expression values and the MRC classification that outperformed all currently used methods to predict refractory disease in intensively treated adult AML patients. PS29MRC demonstrates that it is possible to identify patients at risk of treatment failure in AML at diagnosis with high specificity. Figure 1. Kaplan-Meier estimates showing overall survival of AML patients in the validation set according to PS29MRC Figure 1. Kaplan-Meier estimates showing overall survival of AML patients in the validation set according to PS29MRC Figure 2. Figure 2. Disclosures No relevant conflicts of interest to declare.

Introduction In Acute Myeloid Leukemia (AML) internal tandem duplications (ITD) in the fms-related tyrosine kinase 3 (FLT3) are a frequent event associated with an unfavorable prognosis. At diagnosis, the FLT3-ITD status is routinely assessed by fragment analysis of PCR-amplified cDNA. However, this assay only provides information on the length but not on the position and sequence of the insertion. Therefore, it is attractive to overcome this limitation by the use of high-throughput amplicon sequencing (HTAS) as an alternative strategy for FLT3-ITD detection. To proof the feasibility and accuracy of this approach we performed HTAS on 260 AML patients, of which 250 were FLT3-ITD positive according to routine diagnostics. Patients and Methods All samples were obtained from patients treated on the German Acute Myeloid Leukemia Cooperative Group (AMLCG) trials 1999, 2004 and 2008. All patients received intensive induction therapy with curative intent. At diagnosis, patients had a median age of 60 years (range, 18-80 years). Additional molecular marker were screened routinely: NPM1 mutation (62%), KMT2A-PTD (8%), CEBPA mutations (8%). According to the ELN-classification patients clustered into the following groups: ELN intermediate I (70%), intermediate II (21%) or adverse (9%). A normal karyotype was observed in 71%, while 29% had an aberrant karyotpye. All patient samples were analyzed routinely by FLT3 fragment analysis. For HTAS of FLT3 we used custom FLT3 cDNA primers including barcode and adapter-sequences enabling a one-step PCR-protocol. Sequencing was performed (2x250bp paired end) on a MiSeq (Illumina). Per run, up to 96 samples were sequenced, yielding a median of 79,110 reads per amplicon (range: 31,996 - 259,783). As controls, cDNA from FLT3-ITD positive (Molm-13) and negative (HL60) cell lines were used. Sequencing data were aligned to the FLT3 cDNA reference (NM_004119.2) and FLT3-ITDs were called using Pindel software (version 0.2.5a7). Results Based on the HTAS results obtained from the FLT3 wild-type control HL60, we set the cut-off for ITD detection at a variant allele frequency (VAF) of 0.5%. Using this threshold, all patients which were assessed to be FLT3-ITD negative in diagnostic routine, were also negative in HTAS. FLT3-ITDs were detected by HTAS in 242 out of 250 (97%) patients who were FLT3-ITD positive patients according to routine fragment analysis. For six out of the 8 remaining patients, no valid ITD was detected by HTAS possibly due to one of the following reasons: a low mutational burden resulting in a VAF below the cut-off level (n=4) or a deletion near the ITD (n=2) potentially interfering with ITD-detection. In total, 308 ITDs were detected in 242 patients by HTAS while in these patients 282 ITDs were detected by routine diagnostics. Of note, HTAS missed 13 subclonal ITDs reported in routine, while 39 additional subclonal ITDs were detected by HTAS only. Overall, HTAS detected a higher number of ITDs per patient (mean: 1.27; range: 1-4) compared to fragment analysis (mean: 1.17; range: 1-3). Patients with more than one ITD according to HTAS showed a trend towards shorter overall and relapse free survival (p=0.105, p=0.104 respectively; Figure 1A). The ITD position (i.e. affected FLT3 domain) based on HTAS did not impact on clinical outcome. There was a significant correlation between the FLT3-ITD levels detected by fragment analysis and HTAS (Pearson, R=0.801, p=0.01; Figure 1B). High FLT3-ITD levels measured by fragment analysis had a significant impact on RFS, whereas this effect was not observed for FLT3-ITD levels measured by HTAS. The quantification of FLT3-ITD by HTAS might be hampered by underestimation of the VAFs of long ITDs that are less likely to be mapped correctly compared to shorter ITDs. Conclusion In summary, our study demonstrates the feasibility of HTAS for FLT3-ITD detection in AML. In particular, the identification of subclonal ITDs with high sensitivity provides additional information with potential prognostic value. Thus, HTAS may serve as a robust tool that could be implemented in future diagnostic routines. However, bioinformatic algorithms for ITD detection may need further improvement, e.g. to optimize ITD quantification and to facilitate the detection of ITDs in combination with deletions. Disclosures Hiddemann: Roche: Other: Grants; Genentech: Other: Grants; Roche: Membership on an entity's Board of Directors or advisory committees.

Radiotherapy is a powerful cure for several types of solid tumours, but its application is often limited because of severe side effects in individual patients. With the aim to find biomarkers capable of predicting normal tissue side reactions we analysed the radiation responses of cells from individual head and neck tumour and breast cancer patients of different clinical radiosensitivity in a multicentric study. Multiple parameters of cellular radiosensitivity were analysed in coded samples of peripheral blood lymphocytes (PBLs) and derived lymphoblastoid cell lines (LCLs) from 15 clinical radio-hypersensitive tumour patients and compared to age- and sex-matched non-radiosensitive patient controls and 15 lymphoblastoid cell lines from age- and sex- matched healthy controls of the KORA study. Experimental parameters included ionizing radiation (IR)-induced cell death (AnnexinV), induction and repair of DNA strand breaks (Comet assay), induction of yH2AX foci (as a result of DNA double strand breaks), and whole genome expression analyses. Considerable inter-individual differences in IR-induced DNA strand breaks and their repair and/or cell death could be detected in primary and immortalised cells with the applied assays. The group of clinically radiosensitive patients was not unequivocally distinguishable from normal responding patients nor were individual overreacting patients in the test system unambiguously identified by two different laboratories. Thus, the in vitro test systems investigated here seem not to be appropriate for a general prediction of clinical reactions during or after radiotherapy due to the experimental variability compared to the small effect of radiation sensitivity. Genome-wide expression analysis however revealed a set of 67 marker genes which were differentially induced 6 h after in vitro-irradiation in lymphocytes from radio-hypersensitive and non-radiosensitive patients. These results warrant future validation in larger cohorts in order to determine parameters potentially predictive for clinical radiosensitivity.

Dose density during early induction has been demonstrated to be one of the prime determinants for treatment efficacy in acute myeloid leukemia (AML). The German AML Cooperative Group has therefore piloted a dose-dense induction regimen sequential high-dose AraC and mitoxantrone followed by pegfilgrastim (S-HAM) in which 2 induction cycles are applied over 11 to 12 days instead of 25 to 29 days as used in conventional double induction, thereby increasing dose density 2-fold. Of 172 de novo AML patients (excluding acute promyelocytic leukemia), 61% reached a complete remission, 22% a complete remission with incomplete peripheral recovery, 7% had persistent leukemia, 10% died (early death) resulting in an overall response rate of 83%. Kaplan-Meier estimated survival at 2 years was 61% for the whole group (patients with unfavorable karyotypes, 38%; patients with favorable karyotypes, 69%; patients with intermediate karyotypes, 75%) after S-HAM treatment. Importantly, the compression of the 2 induction cycles into the first 11 to 12 days of treatment was beneficial for normal hematopoiesis as demonstrated by a significantly shortened duration of critical neutropenia of 31 days compared with 46 days after conventionally timed double induction. (European Leukemia Trial Registry LN_AMLINT_2004_230.)

Background The German AML Intergroup conducted two randomized studies in younger ( Patients and Methods The East German Study Group (OSHO) and the Acute Myeloid Leukemia Cooperative Group (AMLCG) each entered patients from 18 to 59 years into one study and patients aged 60 years and older into another. Each study group randomized upfront 10% of all AML patients into a common standard arm and 90% in the study group specific arm. All patients with de novo AML or AML after myelodysplastic syndrome or cytotoxic treatment were eligible. Chi-squared and Mann-Whitney-U tests were used to detect significant differences between the age groups regarding demographic, clinical and cytogenetic characteristics at baseline. Complete Remission (CR) at 90 days and cumulative probabilities of death were determined for outcome. To avoid bias due to the higher probability of death in older patients, cumulative probabilities of death were calculated for relapsed patients or those who did not achieve CR after 90 days. Other deaths were considered as a competing risk. Results A total of 2435 AML patients were analyzed, 1132 in the study A higher rate of CR at 90 days was observed in the younger (66%) than in the older (51%) patients (p= The cumulative probability of AML-related death was lower in younger patients than in older patients (p The probability of dying from AML was lowest for the younger patients with de novo AML [27% (95% CI 24% to 29%) at 1 year and 41% (95% CI 38% to 44%) at 3 years] and highest for those with secondary AML [38% (95% CI 32% to 44%) at 1 year and 56% (95% CI 49% to 62%) at 3 years (p=0.0001)], with similar differences being observed in the older patients (p=0.0001, Figure 1b). In the younger patients, CR at 90 days was lower in the standard (58%) than in the study arm (66%, p=0.0558), while AML related death was 29% and 27% at 1 year and 44% and 39% at 3 years respectively. In the older patients CR at 90 days was 52% vs. 51%, AML related death at 1 year 45% and 45% and at 3 years 63% and 69% for study arm and standard arm, respectively (Figure 1c). Conclusion This analysis reveals significant differences in gender, laboratory characteristics and proportion of secondary AML in elderly compared to younger AML patients. While there was no clear difference in cytogenetic risk groups, favorable molecular markers were more frequent in younger patients. Clear differences in CR rates after 90 days of therapy and AML related death rate were seen in regard to age ( Disclosures Niederwieser: Novartis: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Hoffmann:Novartis Oncology Europe: Research Funding. Krug:Sunesis; Clavis Pharma; usa Pharma, Catapult Cell Therapy, Gilead, Roche: Membership on an entity's Board of Directors or advisory committees; Sunesis: Speakers Bureau; Boehringer Ingelheim: Research Funding; Novartis; BMS; Roche; Boehringer Ingelheim; Bayer: Honoraria. Hegenbart:Janssen: Honoraria, Other: travel support. Pfirrmann:Novartis Pharma: Consultancy, Honoraria; BMS: Consultancy, Honoraria. Kraemer:TEVA: Other: travel support. Al-Ali:Celgene: Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding.

Hematopoietic growth factors (GFs) are administered to patients who have acute myeloid leukemia (AML) in order to overcome two limitations of chemotherapy: (I) myelotoxicity, and (2) the chemoresistance of minimal residual disease. GFs have been used after chemotherapy in 11 clinical studies, 8 on older age or otherwise high-risk AML. The GFs used were granulocyte-macrophage colony-stimulating factor (GM-CSF) in 7, G-CSF in three and macrophage-CSF in one of the studies. Beneficial effects could be shown on the duration of neutropenia in 8 studies, frequency of infections or fever in 4 studies, mortality or survival in 2 studies and remission rate in 1 study. The benefits in remissions and survival were all found among high-risk patients. One study in younger patients found disadvantages in the remission rate and event-free survival, whereas there was no adverse effect of GF on therapy resistance, leukemic regrowth, or disease-free survival in the other studies. GF priming strategies are based on their stimulation of AML blasts in vitro, their modulation of cellular cytarabine (ARA-C) metabolism and enhancement of clonogenic cell kill by ARA-C. Protective effects of GF against clonogenic cell kill or apoptosis were also described. There are data from 10 clinical studies using GFs before or simultaneously with chemotherapy. One study showed significance, two others a tendency to longer disease-free survival, and two studies showed a trend toward more remissions. A disadvantage in the remission rate and survival was found in one study and prolonged thrombocytopenia in two studies. Nine of ten studies did not find evidence for an adverse effect of GF priming on the course of the disease. In most studies, GF priming was only administered in one or two chemotherapy courses. One study giving four to five courses found a reduction in relapses during the first 6 months. In conclusion, a supportive use of GF may have a place in high-risk, but not standard-risk AML. GF priming approaches may not have been adequately investigated and an extension of this strategy to more treatment courses now appears more promising. Based on the clinical data available, all administration of GF in AML should be regarded as investigational.

Expression of CD34 by leukemic blasts was analyzed in 230 pediatric and 251 adult patients with de novo AML enrolled in two large multicenter trials (AML-BFM-87 and AMLCG respectively). The association between CD34 positivity and morphological classification according to FAB criteria, cytogenetic aberrations, immunophenotypic features and clinical characteristics was investigated. CD34 was expressed (> or = 20%) by leukemic cells from 45% of childhood and 43% of adult AML patients. CD34+ AML was often associated with M1/M2 morphology as well as the coexpression of CD7 and TdT. Translocation t(8;21), inv(16) and chromosome 5 and 7 aberrations were more frequently observed in CD34+ AML. There was a low frequency of CD34 expression in infant AML but no age dependency was evident in adult patients. CD34 expression exerted no influence on the rate of complete remissions (CR) after intensive multidrug induction therapy. In adults, 56% of the CD34-positive and 64% of CD34-negative cases achieved CR (P = 0.29), and the childhood trial even revealed a slight advantage for CD34+ AML with a CR rate of 80% vs. 71% for CD34-negative cases (P = 0.068). Long-term follow-up disclosed no significant differences in remission duration or event-free survival between the CD34-positive and CD34-negative groups. In conclusion, CD34+ AML patients comprise a heterogeneous group with good as well as poor risk factors. Though characterized by some distinct features, CD34 lacks prognostic significance in de novo AML patients submitted to intensive polychemotherapy.

Abstract 425 The introduction of all-trans-retinoic acid (ATRA) in front line therapy of acute promyelocytic leukemia (APL) has improved the outcome of all age groups. In the elderly patients (pts), multi-morbidity and higher vulnerability to chemotherapy-related toxicity are the main problems reducing the chance of cure. This has led to recommendations to reduce the intensity of therapy in elderly APL pts. We report on the long-term outcome of pts with newly diagnosed APL registered in two prospective studies of the German AML Cooperative Group (AMLCG) from December 1994 until June 2011. The therapy consisted of ATRA and anthracycline/ara-C-based induction and consolidation therapy (TAD/HAM–TAD) followed by maintenance therapy as reported previously in younger APL pts (Lengfelder et al. Leukemia 2009;23:2248–2258). In pts ≥60 years (y), the administration of the second induction cycle (HAM with an age adapted cumulative ara-C dose of 6g/sqm) was at the discretion of the treating physician. After December 2005, the pts were included in the ongoing APL protocol and randomized between the AMLCG strategy and the protocols of the Spanish PETHEMA. Among 295 adult pts with newly diagnosed APL, 83 pts (28%) were ≥60y of age. Seventeen elderly pts (20%) were not enrolled in the study, due to death before start of therapy, contraindications against chemotherapy or concomitant other malignancy. Eleven pts randomized in the PETHEMA arm were excluded from the present analysis to cover homogeneity of therapy. In 53 of 55 pts treated according to the AMLCG protocol, results are available. Median age was 67 y (range 60 to 83); 58% were male, 42% female; 68% had low/intermediate and 32% high risk according to Sanz score. Morphology was FAB M3 in 62%, M3v in 38%. Cytogenetics showed t(15;17) alone in 52%, and combination with other abnormalities in 48% of pts. The bcr1/bcr2 transcript of PML/RARA was found in 41% and the bcr3 transcript in 59% of pts. Forty-four pts (83%) achieved complete remission (CR). Early death (ED) occurred in 9 pts (17%). Median time to ED was 12 days (range 2 to 19) after start of therapy. Causes of ED were bleeding, multi-organ failure and sepsis. Manifest APL differentiation syndrome occurred in 25% of pts and WHO grade '3 bleeding, fever/infection or cardiac failure in 8%, 43% and 17% of pts, respectively. After consolidation therapy, 96% of pts were in molecular remission. After a median follow up of 5.3 y (1 day to 12.8 y), the 6-year overall (OS), event free (EFS) and relapse free survival (RFS) and the cumulative incidence of relapse (CIR) were 45%, 41%, 50% and 26%, respectively. The outcome was further analyzed according to risk group, number of induction cycles, and age ≥60y to 69y and ≥70y. Pts with pretreatment white blood cell (WBC) count Disclosures: No relevant conflicts of interest to declare.

The impact of allogeneic blood stem cell transplantation (Allo-SCT) in comparison to conventional chemotherapy (CCT) in AML on quality of life remains unclear mainly due to a lack of studies with long term follow-up. Therefore the German AML-Intergroup initiated a survey on quality of life for patients treated within 1 of 8 German prospective multicenter treatment trials. All patients completed a self-report questionnaire either when they returned for follow-up outpatient visits or by mail. Patients completed the EORTC Quality of Life-Core Questionnaire (QLQ-C30) supplemented by self-assessed concomitant diseases, late treatment effects and demographic details including percentage of disability. 525 patients (median age: 46 years at diagnosis; median follow up period: 9 years) returned their questionnaires, 244 after SCT in 1. CR (189 allo; 55 auto) and 281 after CCT. Recovery-rate of the questionnaires was 55% ranging from 40% to 79% in the different trial cohorts. Due to low numbers after auto-SCT these patients were excluded from further analysis. The ECOG activity index revealed normal activity in 40% and 58% and disabled person card in 63% and 37% of the patients in the allo-SCT and CCT groups, respectively. Impaired vision, cataract surgery, chronic skin disorders and treatment of hormonal disorders were reported significantly more often in allo-SCT-patients, whereas osteoarthritis, cardiac insufficiency and unspecific back pain were slightly more frequent in CCT patients, mainly due to a higher median age in the CCT-group. All QLQC-30 functions except physical functioning and pain were in favor of CCT (p 45 years (odds-ratio 2.57 95%-CI 1.47–4.50) and Allo-SCT (odds ratio 2.10 95%-CI 1.20 – 3.69) showed significant adverse effect on global health status. Similarly unfavorable effects were evaluated for actually concomitant disease and Allo-SCT on fatigue. These results indicate that Allo-SCT compared to intensive chemotherapy had a significant negative impact on quality of life and this needs to be considered when reviewing treatment options.

Trisomy 8 (+8) occurs in about 8–13% of patients with acute myeloid leukemia (AML). However, so far the prognostic impact of this recurrent aberration is unclear. Additional prognostic factors and different consolidation therapies may influence prognosis in this disease entity. Therefore, the German AML Intergroup analyzed 198 adult patients (median age 49 (17–60) years; 172 de novo and 26 secondary AML) with trisomy 8 treated between 1993 and 2002 in eight prospective German AML treatment trials. Patients with t(8;21), inv(16) or abn11q23 and an additional +8 were not included in the study. Clinical, diagnostic and laboratory data were reviewed for consistency and completeness before analysis by a central coordination center. Ninety-two (46%) patients had +8 as a sole aberration, 39 (20%) had one additional secondary aberration and 67 (34%) had +8 within complex karyotypes with at least three independent abnormalities. Trisomy 8 was frequently accompanied by other trisomies (53/198), especially by +21 (16/198) or +22 (13/198). Complete remission rate after two induction therapies was 62% for all patients. An additional +21 (odds ratio 0.17; 95% CI 0.05–0.57) and a secondary AML (odds ratio 0.38; 95% CI 0.16–0.90) were negative prognostic factors for treatment response. Only 25% of patients with an additional +21 reached CR criteria. Disease free survival (DFS) was 18% and overall survival (OS) 19% after 5 years for all patients, respectively. Patients with +8 as a sole aberration had a 5-year OS of 20%, with one additional secondary aberration of 32% and with a complex karyotype of only 8% (p=0.005). All but one patient with an additional +21 died within the first two years (p Multivariate analysis revealed age (difference 10 years hazard ratio (HR) 1.30; p In conclusion, the data of this large cohort of patients indicate that AML with trisomy 8 is a heterogeneous entity. Neither allogeneic nor autologous transplantation proved superiority compared to high-dose cytarabine based consolidation therapy. For the majority of patients alternative therapeutic approaches are needed to achieve durable remissions in the future.

The Armadillo repeat-containing X-linked protein 1 (ARMCX1)gene encodes a member of the ALEX family of proteins and is located on the X chromosome. We found this gene aberrantly expressed in acute myeloid leukemia (AML) cells. We analyzed ARMCX1 expression in a cohort of 508 AML patients who received intensive chemotherapy within AMLCG clinical trial. Expression levels of ARMCX1 were determined in pretreatment bone marrow or peripheral blood samples by using oligonucleotide microarrays (GSE37642). High transcript levels (dichotomized at the median expression) of ARMCX1 were predictors for inferior overall survival (OS) (p=0.0027, Log-Rank test) and a lower rate of complete remission (CR) (p=0.0017). Older patients (≥ 60 years) showed an elevated incidence of high ARMCX1 expression compared to younger patients ( Multivariate logistic regression did not show any association between ARMCX1 expression and sex, lactatdehydrogenase (LDH) or leukocyte count (WBC). Interestingly, high expression of ARMCX1 was strongly associated with high United Kingdom Medical Research Council (MRC) risk classification (p Evaluation of ARMCX1 expression against a clinical multivariate Cox-Regression model (age, gender) showed that dichotomized ARMCX1 added a significant amount of information to the model and was a risk factor for OS (p=0.0020, HR= 1.377 (95%-CI 1.124, 1.686)). Strikingly, including MRC risk classification into the multivariate Cox-Regression model high ARMCX1 expression remained a significant risk factor for OS (p=0.0413, HR=1.243 (95%-CI 1.009, 1.531)). Taken together, we analyzed ARMCX1 expression levels in a large AML patient cohort. In this study, high ARMCX1 expression levels were identified as a negative prognostic factor for AML patients with respect to survival and remission. Disclosures Hiddemann: Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Research Funding. Stelljes:Pfizer: Consultancy.