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Metzeler, Klaus H.

https://orcid.org/0000-0003-3920-7490

Mayo Clinic

University Hospital Leipzig

Citations 8

Wide variability and inconsistency in reporting of results of Myelodysplastic Syndromes/neoplasms (MDS) clinical trials: An icMDS systematic review of published manuscripts
Getz, Ted M. , Pugh, Kelly , Brunner, Andrew M. , Borate, Uma , Buckstein, Rena , Hasserjian, Robert P. , Fenaux, Pierre, Sallman, David A. , Nimer, Stephen D. , Little, Richard F. , Odenike, Olatoyosi , Greenberg, Peter L. , Xu, Mina L. , Bejar, Rafael, Patnaik, Mrinal M. , Padron, Eric , Gore, Steven D. , Bennett, John M. , Metzeler, Klaus H. , Pleyer, Lisa , Loosdrecht, Arjan van de, Cluzeau, Thomas , Mufti, Ghulam, Sébert, Marie , Götze, Katharina S. , Miyazaki, Yasushi , Al‐Kali, Aref , Yacoub, Abdulraheem , Li, Bing, Stahl, Maximilian , Götze, Katharina , Brunner, Andrew, Bewersdorf, Jan Philipp , Dezern, Amy Elizabeth , Kewan, Tariq Zuheir , Platzbecker, Uwe , Sekeres, Mikkael A. , Wei, Andrew H. , Kordasti, Shahram , Roboz, Gail J. , Savona, Michael R. , Loghavi, Sanam , Fenaux, Pierre , Hourigan, Christopher S. , Porta, Matteo Giovanni Della , Santini, Valeria , Efficace, Fabio , Taylor, Justin , Kim, Tae Kon , Halene, Stephanie , Komrokji, Rami S. , Griffiths, Elizabeth A. , Xie, Zhuoer , Bejar, Rafael , Sanz, Guillermo , Figueroa, María E. , Carraway, Hetty E. , Abdel‐Wahab, Omar , Starczynowski, Daniel T. , Boultwood, Jacqueline , Daver, Naval , Churpek, Jane E. , Majeti, Ravindra , List, Alan F. , Orgueira, Adrián Mosquera , Solé, Françesc , Steensma, David P. , Adès, Lionel , Lanino, Luca , Madanat, Yazan F. , Platzbecker, Anne Sophie , Lindsley, R Coleman , Gurnari, Carmelo , Li, Bing, Kotsianidis, Ιoannis , Zeidan, Amer M.

Blood | December 4, 2025 | Volume: 146 | Issue: Supplement 1 | Pages: 3852-3852

10.1182/blood-2025-3852 Get It

Abstract Introduction: Standardized reporting of clinical trials results for MDS is essential to improve clinical interpretation and cross-study comparison. However, reporting of patient characteristics, response criteria, and endpoints in publications is often inconsistent; there is no systemic analysis of MDS trial reporting available. We conducted a systematic review of published MDS trial manuscripts on behalf of the international consortium for MDS (icMDS) to assess variability in reporting practices. Methods We searched ClinicalTrials.gov to identify all clinical trials registered for adults (≥18 years) with MDS that reported results between 2015-2024. Clinical trials that included acute myeloid leukemia (AML) or MDS/myeloproliferative neoplasms (MPN) were included if they enrolled ≥5 MDS patients. We excluded trials without an MDS cohort; non-therapeutic trials; trials focused on transplant interventions; or those which enrolled solid malignancies or other hematologic malignancies (chronic myeloid leukemia or lymphoid diseases). Finally, trials were required to have a manuscript available on Larvol, PubMed, or Google Scholar. Trials were categorized by disease risk (lower-risk [LR] vs. higher-risk [HR]) and trial phase (early phase [EP] vs. late phase [LP]). Results We identified 502 MDS trials on ClinicalTrials.gov, of which 351 did not meet inclusion criteria and 79 lacked a manuscript. A total of 72 trials (32 EP, 40 LP) with 80 publications (34 EP, 46 LP) were analyzed. Frequently reported baseline characteristics included age (100% EP, 100% LP), disease risk (74% EP, 74% LP), Eastern Cooperative Oncology Group performance status (85% EP, 72% LP), prior treatments (71% EP, 67% LP), and RBC transfusion dependency (32% EP, 70% LP). Less frequently reported characteristics included blood counts (hemoglobin [Hb; 38% EP, 54% LP], platelet count [38% EP, 54% LP], neutrophil count [24% EP and LP]) and bone marrow blasts (29% EP, 43% LP). Although disease risk was widely reported, definitions varied: IPSS and IPSS-R were each reported in 54% of manuscripts, while IPSS-M appeared in only 3%. Cytogenetic risk was separately reported in 39% of manuscripts (38% EP, 39% LP), and mutational data in 45% (47% EP, 43% LP). Responses per IWG 2006 criteria were reported in 84% of manuscripts. The primary endpoint involved safety/tolerability in 85% of EP manuscripts, though definitions were variable; recommended phase 2 dose was the most common (26% of EP manuscripts). In LP trials, primary endpoints were risk-specific: transfusion independence (TI) in 77% of LR, overall response rate (ORR) in 28% of HR, and complete remission (CR) or overall survival (OS) in 22% of HR. In HR manuscripts, CR was reported in 100%, ORR in 73%, hematologic improvement (HI) in 48%, RBC-TI in 23%, and OS in 80%. However, seven different definitions were used for ORR: CR + marrow CR + partial remission + HI per IWG 2006 was most common (35%). Event-free survival was reported in 25%; progression-free survival and relapse-free survival in 13%; and leukemia-free survival in 5%. Early mortality rate was reported in 35% (18% EP, 56% LP) and transplant rate in 58% (50% EP, 67% LP). Only 47% of HR and 90% of LR manuscripts identified HI-eligible patients. In LR-MDS, RBC-TI was reported in 72% of manuscripts but used six definitions. The most common were RBC-TI ≥8 weeks at any time during treatment (24%), ≥8 weeks within 28 weeks of treatment (13%), ≥8 weeks with Hb increase ≥1.0 (4%), ≥12 weeks with Hb increase ≥1.5 (4%), and ≥16 weeks within 24 weeks of treatment (12%). The remainder did not report RBC-TI, did not define it, or used a custom definition not used in another trial. HI was reported in 80% of LR papers with most of those reporting HI using IWG 2006 criteria (90%). Conclusion Reporting of baseline characteristics, response criteria, and outcomes is inconsistent in MDS clinical trials, with wide variability in response definitions, including ORR and TI. This heterogeneity limits interpretability, hampers historical comparisons and may obscure efficacy signals. Our findings highlight the need for standardized reporting guidelines to ensure clarity and consistency in MDS trial publications. As a next phase of this effort, we will conduct a formal Delphi process among icMDS experts to establish consensus recommendations for minimal and optimal MDS clinical trial reporting in manuscripts by disease risk (LR/HR) and trial phase (EP/LP).
Differential Clinical Impact Of Gene Mutations and Their Combinations In Primary Cytogenetically Normal Acute Myeloid Leukemia (CN-AML)
Maharry, Kati , Becker, Heiko , Metzeler, Klaus H. , Whitman, Susan P., Eisfeld, Ann‐Kathrin , Schwind, Sebastian , Wu, Yue-Zhong, Kolitz, Jonathan E. , Baer, Maria R. , Powell, Bayard L., Bucci, Donna, Carroll, Andrew J. , Stone, Richard M. , Marcucci, Guido , Bloomfield, Clara D. , Papaioannou, Dimitrios , Mrózek, Krzysztof , Mendler, Jason H. , Nicolet, Deedra , Caligiuri, Michael A. , Volinia, Stefano

Blood | October 14, 2019 | Volume: 122 | Issue: 21 | Pages: 2540-2540

10.1182/blood.v122.21.2540.2540 Get It

Abstract In CN-AML, mutations of specific genes have prognostic significance and are used for treatment guidance. However, these mutations are in general not mutually exclusive and CN-AML patients (pts) frequently harbor mutational combinations with unclear prognostic significance because of the concurrent presence of mutations with favorable (CEBPA, NPM1) and unfavorable (ASXL1, DNMT3A, IDH1, IDH2, FLT3-ITD, MLL-PTD, RUNX1, TET2, WT1) impact on outcome. Here, we report the frequency and clinical significance of isolated mutations and their combinations in 364 CN-AML pts. Younger [<60 years (y); n=163] and older (≥60 y; n=201) pts were intensively treated on frontline CALGB/Alliance protocols and, per protocol, did not undergo allogeneic stem cell transplantation in first complete remission (CR). Median follow-up for pts alive was 8.7 y. Pts were analyzed centrally for mutations in the ASXL1, CEBPA, DNMT3A, IDH1, IDH2, NPM1, RUNX1, TET2, and WT1 genes and the presence of FLT3-ITD, FLT3-TKD and MLL-PTD. We found that 99% of pts had ≥1 and 88% ≥2 of the 12 mutations. Specifically, 11% of pts had 1 gene mutated (n1), 40% had 2 (n2), 31% 3 (n3), and 18% harbored ≥4 mutated genes (n4). The distribution of the different n groups in younger and older pts was similar (Fig 1). The expected frequency of each mutated gene in every numerical (n) group was calculated as follows: [no. of pts with the mutated gene] x [total no. of mutations in the n group] / [total no. of mutations in all pts], and compared with the observed frequency. CEBPA, IDH2, NPM1, and RUNX1 mutations were overrepresented in the n1 and n2 groups (P<.001, P<.001, P=.002, P=.02, respectively) and thus likely represent “early” events in leukemogenesis. In contrast, DNMT3A, FLT3-ITD, and TET2 mutations were more frequent in the n3 and n4 groups (P=.008, P<.001, P=.02, respectively) suggesting that they are likely “late” events. The distribution among age groups and clinical impact of the “early” mutations (i.e., CEBPA, NPM1, IDH2) presenting as isolated mutations or in combination with other mutations were then investigated. Isolated RUNX1 mutations could not be evaluated due to small sample size. Younger pts were more likely to harbor an isolated “early” mutated gene than older pts (21% v 12%, P=.03). Specifically, isolated CEBPA and NPM1 mutations were more frequent in younger pts compared with the older (7% v 2%, P=.007; 7% v 3%, P=.07, respectively). In pts with isolated CEBPA mutations, these were always bi-allelic. Single “early” mutated genes varied in their impact on CR achievement (CEBPA: 100%, NPM1: 94%, IDH2: 67%), and overall survival (OS; 3-y OS: CEBPA: 87%, NPM1: 69%, IDH2: 22%). Acquisition of additional mutations adversely modified the prognostic significance of favorable “early” mutations in the CEBPA (Fig 2A) and NPM1 (Fig 2B) genes, but left unchanged the unfavorable effect of IDH2 mutations (Fig 2C). Two mutational combinations were exceptions to this: younger pts with both NPM1 and DNMT3A mutations (8 pts) had an excellent prognosis with 3-y OS of 100%; and older pts with concurrent NPM1 and IDH2 mutations (9 pts; all IDH2 mutations were in codon R140) had a high 3-y OS rate of 67%. We conclude that CEBPA and NPM1 mutations mainly define pts with favorable prognosis when they present as single markers, whereas mutated IDH2 predominantly associates with adverse outcome. The NPM1+DNMT3A and NPM1+IDH2 mutational patterns may define novel favorable molecular subtypes in younger and older CN-AML pts, respectively, but these results require corroboration in larger pt cohorts. Disclosures: Mrózek: AMERICAN SOCIETY OF HEMATOLOGY: I will review abstracls submitted for presentation at the 55th ASH Annual Meeting in the 611 category Other. Eisfeld:AMERICAN SOCIETY OF HEMATOLOGY: I will review abstracls submitted for presentation at the 55th ASH Annual Meeting in the 608 category Other.
Clinical Role of microRNAs in Cytogenetically Normal Acute Myeloid Leukemia: miR-155 Upregulation Independently Identifies High-Risk Patients
Marcucci, Guido , Maharry, Kati , Metzeler, Klaus H. , Wu, Yue-Zhong, Mrózek, Krzysztof , Kohlschmidt, Jessica, Whitman, Susan P., Schwind, Sebastian , Becker, Heiko , Eisfeld, Ann‐Kathrin , Carroll, Andrew J. , Powell, Bayard L., Kolitz, Jonathan E. , Garzon, Ramiro , Stone, Richard M. , Bloomfield, Clara D. , Volinia, Stefano , Nicolet, Deedra , Mendler, Jason H. , Caligiuri, Michael A.

Journal of Clinical Oncology | May 7, 2013 | Volume: 31 | Issue: 17 | Pages: 2086-2093

10.1200/jco.2012.45.6228 Get It

Purpose To evaluate the impact of miR-155 on the outcome of adults with cytogenetically normal (CN) acute myeloid leukemia (AML) in the context of other clinical and molecular prognosticators and to gain insight into the leukemogenic role of this microRNA. Patients and Methods We evaluated 363 patients with primary CN-AML. miR-155 levels were measured in pretreatment marrow and blood by NanoString nCounter assays that quantified the expression of the encoding gene MIR155HG. All molecular prognosticators were assessed centrally. miR-155–associated gene and microRNA expression profiles were derived using microarrays. Results Considering all patients, high miR-155 expression was associated with a lower complete remission (CR) rate (P < .001) and shorter disease-free survival (P = .001) and overall survival (OS; P < .001) after adjusting for age. In multivariable analyses, high miR-155 expression remained an independent predictor for a lower CR rate (P = .007) and shorter OS (P < .001). High miR-155 expressers had approximately 50% reduction in the odds of achieving CR and 60% increase in the risk of death compared with low miR-155 expressers. Although high miR-155 expression was not associated with a distinct microRNA expression profile, it was associated with a gene expression profile enriched for genes involved in cellular mechanisms deregulated in AML (eg, apoptosis, nuclear factor-κB activation, and inflammation), thereby supporting a pivotal and unique role of this microRNA in myeloid leukemogenesis. Conclusion miR-155 expression levels are associated with clinical outcome independently of other strong clinical and molecular predictors. The availability of emerging compounds with antagonistic activity to microRNAs in the clinic provides the opportunity for future therapeutic targeting of miR-155 in AML.
inv(16)/t(16;16) acute myeloid leukemia with non–type A CBFB-MYH11 fusions associate with distinct clinical and genetic features and lack KIT mutations
Schwind, Sebastian , Edwards, Colin G., Mrózek, Krzysztof , Maharry, Kati , Wu, Yue-Zhong, Paschka, Peter , Eisfeld, Ann‐Kathrin , Hoellerbauer, Pia , Becker, Heiko , Metzeler, Klaus H. , Curfman, John, Kohlschmidt, Jessica, Prior, Thomas W., Kolitz, Jonathan E. , Blum, William , Pettenati, Mark J., Cin, Paola Dal , Carroll, Andrew J. , Larson, Richard A. , Volinia, Stefano , Marcucci, Guido , Bloomfield, Clara D. , Nicolet, Deedra , Caligiuri, Michael A. , Larson, Richard A

Blood | November 17, 2012 | Volume: 121 | Issue: 2 | Pages: 385-391

10.1182/blood-2012-07-442772 Get It

Abstract The inv(16)(p13q22)/t(16;16)(p13;q22) in acute myeloid leukemia results in multiple CBFB-MYH11 fusion transcripts, with type A being most frequent. The biologic and prognostic implications of different fusions are unclear. We analyzed CBFB-MYH11 fusion types in 208 inv(16)/t(16;16) patients with de novo disease, and compared clinical and cytogenetic features and the KIT mutation status between type A (n = 182; 87%) and non–type A (n = 26; 13%) patients. At diagnosis, non–type A patients had lower white blood counts (P = .007), and more often trisomies of chromosomes 8 (P = .01) and 21 (P < .001) and less often trisomy 22 (P = .02). No patient with non–type A fusion carried a KIT mutation, whereas 27% of type A patients did (P = .002). Among the latter, KIT mutations conferred adverse prognosis; clinical outcomes of non–type A and type A patients with wild-type KIT were similar. We also derived a fusion-type–associated global gene-expression profile. Gene Ontology analysis of the differentially expressed genes revealed—among others—an enrichment of up-regulated genes involved in activation of caspase activity, cell differentiation and cell cycle control in non–type A patients. We conclude that non–type A fusions associate with distinctclinical and genetic features, including lack of KIT mutations, and a unique gene-expression profile.
Prognostic Significance of the European LeukemiaNet Standardized System for Reporting Cytogenetic and Molecular Alterations in Adults With Acute Myeloid Leukemia
Mrózek, Krzysztof , Marcucci, Guido , Maharry, Kati , Becker, Heiko , Whitman, Susan P., Metzeler, Klaus H. , Schwind, Sebastian , Wu, Yue-Zhong, Kohlschmidt, Jessica, Pettenati, Mark J., Heerema, Nyla A. , Block, AnneMarie W., Patil, Shivanand R., Baer, Maria R. , Kolitz, Jonathan E. , Moore, Joseph O. , Carroll, Andrew J. , Stone, Richard M. , Larson, Richard A. , Bloomfield, Clara D. , Nicolet, Deedra , Larson, Richard A

Journal of Clinical Oncology | September 18, 2012 | Volume: 30 | Issue: 36 | Pages: 4515-4523

10.1200/jco.2012.43.4738 Get It

Purpose To evaluate the prognostic significance of the international European LeukemiaNet (ELN) guidelines for reporting genetic alterations in acute myeloid leukemia (AML). Patients and Methods We analyzed 1,550 adults with primary AML, treated on Cancer and Leukemia Group B first-line trials, who had pretreatment cytogenetics and, for cytogenetically normal patients, mutational status of NPM1, CEBPA, and FLT3 available. We compared complete remission (CR) rates, disease-free survival (DFS), and overall survival (OS) among patients classified into the four ELN genetic groups (favorable, intermediate-I, intermediate-II, adverse) separately for 818 younger (age < 60 years) and 732 older (age ≥ 60 years) patients. Results The percentages of younger versus older patients in the favorable (41% v 20%; P < .001), intermediate-II (19% v 30%; P < .001), and adverse (22% v 31%; P < .001) genetic groups differed. The favorable group had the best and the adverse group the worst CR rates, DFS, and OS in both age groups. Both intermediate groups had significantly worse outcomes than the favorable but better than the adverse group. Intermediate-I and intermediate-II groups in older patients had similar outcomes, whereas the intermediate-II group in younger patients had better OS but not better CR rates or DFS than the intermediate-I group. The prognostic significance of ELN classification was confirmed by multivariable analyses. For each ELN group, older patients had worse outcomes than younger patients. Conclusion The ELN classification clearly separates the genetic groups by outcome, supporting its use for risk stratification in clinical trials. Because they have different proportions of genetic alterations and outcomes, younger and older patients should be reported separately when using the ELN classification.
miR-3151 interplays with its host gene BAALC and independently affects outcome of patients with cytogenetically normal acute myeloid leukemia
Eisfeld, Ann‐Kathrin , Marcucci, Guido , Maharry, Kati , Schwind, Sebastian , Radmacher, Michael D., Becker, Heiko , Mrózek, Krzysztof , Whitman, Susan P., Metzeler, Klaus H. , Mendler, Jason H. , Wu, Yue-Zhong, Liyanarachchi, Sandya , Baer, Maria R. , Powell, Bayard L., Carter, Thomas H. , Moore, Joseph O. , Kolitz, Jonathan E. , Wetzler, Meir , Larson, Richard A. , Tanner, Stephan M., Chapelle, Albert de la , Bloomfield, Clara D. , Nicolet, Deedra , Patel, Ravi Kumar , Caligiuri, Michael A. , Larson, Richard A

Blood | April 24, 2012 | Volume: 120 | Issue: 2 | Pages: 249-258

10.1182/blood-2012-02-408492 Get It

Abstract High BAALC expression levels are associated with poor outcome in cytogenetically normal acute myeloid leukemia (CN-AML) patients. Recently, miR-3151 was discovered in intron 1 of BAALC. To evaluate the prognostic significance of miR-3151 expression levels and to gain insight into the biologic and prognostic interplay between miR-3151 and its host, miR-3151 and BAALC expression were measured in pretreatment blood of 179 CN-AML patients. Gene-expression profiling and miRNA-expression profiling were performed using microarrays. High miR-3151 expression was associated with shorter disease-free and overall survival, whereas high BAALC expression predicted failure of complete remission and shorter overall survival. Patients exhibiting high expression of both miR-3151 and BAALC had worse outcome than patients expressing low levels of either gene or both genes. In gene-expression profiling, high miR-3151 expressers showed down-regulation of genes involved in transcriptional regulation, posttranslational modification, and cancer pathways. Two genes, FBXL20 and USP40, were validated as direct miR-3151 targets. The results of the present study show that high expression of miR-3151 is an independent prognosticator for poor outcome in CN-AML and affects different outcome end points than its host gene, BAALC. The combination of both markers identified a patient subset with the poorest outcome. This interplay between an intronic miR and its host may have important biologic implications.
Age-Related Prognostic Impact of Different Types of DNMT3A Mutations in Adults With Primary Cytogenetically Normal Acute Myeloid Leukemia
Marcucci, Guido , Metzeler, Klaus H. , Schwind, Sebastian , Becker, Heiko , Maharry, Kati , Mrózek, Krzysztof , Radmacher, Michael D., Kohlschmidt, Jessica, Whitman, Susan P., Wu, Yue-Zhong, Powell, Bayard L., Carter, Thomas H. , Kolitz, Jonathan E. , Wetzler, Meir , Carroll, Andrew J. , Baer, Maria R. , Moore, Joseph O. , Larson, Richard A. , Bloomfield, Clara D. , Nicolet, Deedra , Caligiuri, Michael A. , Larson, Richard A

Journal of Clinical Oncology | January 31, 2012 | Volume: 30 | Issue: 7 | Pages: 742-750

10.1200/jco.2011.39.2092 Get It

Purpose To determine the frequency of DNMT3A mutations, their associations with clinical and molecular characteristics and outcome, and the associated gene- and microRNA-expression signatures in primary cytogenetically normal acute myeloid leukemia (CN-AML). Patients and Methods Four hundred fifteen previously untreated adults were analyzed for DNMT3A mutations and established prognostic gene mutations and expression markers. Gene- and microRNA-expression profiles were derived using microarrays. Results Younger (< 60 years; n = 181) and older (≥ 60 years; n = 234) patients had similar frequencies of DNMT3A mutations (35.3% v 33.3%). Missense mutations affecting arginine codon 882 (R882-DNMT3A) were more common (n = 92; 62%) than those affecting other codons (non–R882-DNMT3A). DNMT3A-mutated patients did not differ regarding complete remission rate, but had shorter disease-free survival (DFS; P = .03) and, by trend, overall survival (OS; P = .07) than DNMT3A–wild-type patients. In multivariable analyses, DNMT3A mutations remained associated with shorter DFS (P = .01), but not with shorter OS. When analyzed separately, the two DNMT3A mutation types had different significance by age group. Younger patients with non–R882-DNMT3A mutations had shorter DFS (P = .002) and OS (P = .02), whereas older patients with R882-DNMT3A mutations had shorter DFS (P = .005) and OS (P = .002) after adjustment for other clinical and molecular prognosticators. Gene- and microRNA-expression signatures did not accurately predict DNMT3A mutational status. Conclusion DNMT3A mutations are frequent in CN-AML, and their clinical significance seems to be age dependent. DNMT3A-R882 mutations are associated with adverse prognosis in older patients, and non–R882-DNMT3A mutations are associated with adverse prognosis in younger patients. Low accuracy of gene- and microRNA-expression signatures in predicting DNMT3A mutation status suggested that the role of these mutations in AML remains to be elucidated.
ASXL1 mutations identify a high-risk subgroup of older patients with primary cytogenetically normal AML within the ELN Favorable genetic category
Metzeler, Klaus H. , Becker, Heiko , Maharry, Kati , Radmacher, Michael D., Kohlschmidt, Jessica, Mrózek, Krzysztof , Whitman, Susan P., Wu, Yue-Zhong, Schwind, Sebastian , Powell, Bayard L., Carter, Thomas H. , Wetzler, Meir , Moore, Joseph O. , Kolitz, Jonathan E. , Baer, Maria R. , Carroll, Andrew J. , Larson, Richard A. , Marcucci, Guido , Bloomfield, Clara D. , Nicolet, Deedra , Caligiuri, Michael A. , Larson, Richard A

Blood | October 27, 2011 | Volume: 118 | Issue: 26 | Pages: 6920-6929

10.1182/blood-2011-08-368225 Get It

Abstract The associations of mutations in the enhancer of trithorax and polycomb family gene ASXL1 with pretreatment patient characteristics, outcomes, and gene-/microRNA-expression profiles in primary cytogenetically normal acute myeloid leukemia (CN-AML) are unknown. We analyzed 423 adult patients for ASXL1 mutations, other prognostic gene mutations, and gene-/microRNA-expression profiles. ASXL1 mutations were 5 times more common in older (≥ 60 years) patients (16.2%) than those younger than 60 years (3.2%; P < .001). Among older patients, ASXL1 mutations associated with wild-type NPM1 (P < .001), absence of FLT3-internal tandem duplications (P = .002), mutated CEBPA (P = .01), and with inferior complete remission (CR) rate (P = .04), disease-free survival (DFS; P = .03), overall survival (OS; P = .006), and event-free survival (EFS; P = .002). Within the European LeukemiaNet (ELN) genetic categories of older CN-AML, ASXL1 mutations associated with inferior CR rate (P = .02), OS (P < .001), and EFS (P < .001) among ELN Favorable, but not among ELN Intermediate-I patients. Multivariable analyses confirmed associations of ASXL1 mutations with unfavorable CR rate (P = .03), DFS (P < .001), OS (P < .001), and EFS (P < .001) among ELN Favorable patients. We identified an ASXL1 mutation-associated gene-expression signature, but no microRNA-expression signature. This first study of ASXL1 mutations in primary CN-AML demonstrates that ASXL1mutated older patients, particularly within the ELN Favorable group, have unfavorable outcomes and may be candidates for experimental treatment approaches.