Patients with acute myeloid leukemia (AML) and a FLT3 mutation have poor outcomes. We conducted a phase 3 trial to determine whether the addition of midostaurin - an oral multitargeted kinase ...inhibitor that is active in patients with a FLT3 mutation - to standard chemotherapy would prolong overall survival in this population.
We screened 3277 patients, 18 to 59 years of age, who had newly diagnosed AML for FLT3 mutations. Patients were randomly assigned to receive standard chemotherapy (induction therapy with daunorubicin and cytarabine and consolidation therapy with high-dose cytarabine) plus either midostaurin or placebo; those who were in remission after consolidation therapy entered a maintenance phase in which they received either midostaurin or placebo. Randomization was stratified according to subtype of FLT3 mutation: point mutation in the tyrosine kinase domain (TKD) or internal tandem duplication (ITD) mutation with either a high ratio (>0.7) or a low ratio (0.05 to 0.7) of mutant to wild-type alleles (ITD high and ITD low, respectively). Allogeneic transplantation was allowed. The primary end point was overall survival.
A total of 717 patients underwent randomization; 360 were assigned to the midostaurin group, and 357 to the placebo group. The FLT3 subtype was ITD (high) in 214 patients, ITD (low) in 341 patients, and TKD in 162 patients. The treatment groups were well balanced with respect to age, race, FLT3 subtype, cytogenetic risk, and blood counts but not with respect to sex (51.7% in the midostaurin group vs. 59.4% in the placebo group were women, P=0.04). Overall survival was significantly longer in the midostaurin group than in the placebo group (hazard ratio for death, 0.78; one-sided P=0.009), as was event-free survival (hazard ratio for event or death, 0.78; one-sided P=0.002). In both the primary analysis and an analysis in which data for patients who underwent transplantation were censored, the benefit of midostaurin was consistent across all FLT3 subtypes. The rate of severe adverse events was similar in the two groups.
The addition of the multitargeted kinase inhibitor midostaurin to standard chemotherapy significantly prolonged overall and event-free survival among patients with AML and a FLT3 mutation. (Funded by the National Cancer Institute and Novartis; ClinicalTrials.gov number, NCT00651261 .).
Mutations occur in several genes in cytogenetically normal acute myeloid leukemia (AML) cells: the nucleophosmin gene (NPM1), the fms-related tyrosine kinase 3 gene (FLT3), the CCAAT/enhancer binding ...protein alpha gene (CEPBA), the myeloid-lymphoid or mixed-lineage leukemia gene (MLL), and the neuroblastoma RAS viral oncogene homolog (NRAS). We evaluated the associations of these mutations with clinical outcomes in patients.
We compared the mutational status of the NPM1, FLT3, CEBPA, MLL, and NRAS genes in leukemia cells with the clinical outcome in 872 adults younger than 60 years of age with cytogenetically normal AML. Patients had been entered into one of four trials of therapy for AML. In each study, patients with an HLA-matched related donor were assigned to undergo stem-cell transplantation.
A total of 53% of patients had NPM1 mutations, 31% had FLT3 internal tandem duplications (ITDs), 11% had FLT3 tyrosine kinase-domain mutations, 13% had CEBPA mutations, 7% had MLL partial tandem duplications (PTDs), and 13% had NRAS mutations. The overall complete-remission rate was 77%. The genotype of mutant NPM1 without FLT3-ITD, the mutant CEBPA genotype, and younger age were each significantly associated with complete remission. Of the 663 patients who received postremission therapy, 150 underwent hematopoietic stem-cell transplantation from an HLA-matched related donor. Significant associations were found between the risk of relapse or the risk of death during complete remission and the leukemia genotype of mutant NPM1 without FLT3-ITD (hazard ratio, 0.44; 95% confidence interval CI, 0.32 to 0.61), the mutant CEBPA genotype (hazard ratio, 0.48; 95% CI, 0.30 to 0.75), and the MLL-PTD genotype (hazard ratio, 1.56; 95% CI, 1.00 to 2.43), as well as receipt of a transplant from an HLA-matched related donor (hazard ratio, 0.60; 95% CI, 0.44 to 0.82). The benefit of the transplant was limited to the subgroup of patients with the prognostically adverse genotype FLT3-ITD or the genotype consisting of wild-type NPM1 and CEBPA without FLT3-ITD.
Genotypes defined by the mutational status of NPM1, FLT3, CEBPA, and MLL are associated with the outcome of treatment for patients with cytogenetically normal AML.
The prospective randomized, placebo-controlled CALGB 10603/RATIFY trial (Alliance) demonstrated a statistically significant overall survival benefit from the addition of midostaurin to standard ...frontline chemotherapy in a genotypically-defined subgroup of 717 patients with FLT3-mutant acute myeloid leukemia (AML). The risk of death was reduced by 22% on the midostaurin-containing arm. In this post hoc analysis, we analyzed the cumulative incidence of relapse (CIR) on this study and also evaluated the impact of 12 4-week cycles of maintenance therapy. CIR analyses treated relapses and AML deaths as events, deaths from other causes as competing risks, and survivors in remission were censored. CIR was improved on the midostaurin arm (HR = 0.71 (95% CI, 0.54-0.93); p = 0.01), both overall and within European LeukemiaNet 2017 risk classification subsets when post-transplant events were considered in the analysis as events. However, when transplantation was considered as a competing risk, there was overall no significant difference between the risks of relapse on the two randomized arms. Patients still in remission after consolidation with high-dose cytarabine entered the maintenance phase, continuing with either midostaurin or placebo. Analyses were inconclusive in quantifying the impact of the maintenance phase on the overall outcome. In summary, midostaurin reduces the CIR.
The Hedgehog pathway plays an important role in stem-cell biology and malignant transformation. Therefore, we investigated the expression and prognostic impact of Hedgehog pathway members in acute ...myeloid leukemia (AML).
Pretreatment samples from 104 newly diagnosed AML patients (AMLSG 07-04 trial) were analyzed by qPCR, and expression of Hedgehog family members was correlated with clinical outcome. Inhibition of GLI by GANT61 or shRNA was investigated in AML cells in vitro and in vivo.
Expression of receptors Smoothened and Patched-1 and their downstream mediators, GLI1, GLI2, and GLI3, was found in AML patients in contrast to Hedgehog ligands. GLI2 expression had a significant negative influence on event-free survival (EFS), relapse-free survival (RFS), and overall survival (OS; P = 0.037, 0.026, and 0.013, respectively) and was correlated with FLT3 mutational status (P < 0.001). Analysis of a second, independent patient cohort confirmed the negative impact of GLI2 on EFS and OS (P = 0.007 and 0.003, respectively; n = 290). Within this cohort, GLI1 had a negative prognostic impact (P < 0.001 for both EFS and OS). Although AML cells did not express Hedgehog ligands by qPCR, AML patients had significantly increased Desert Hedgehog (DHH) plasma levels compared with healthy subjects (P = 0.002), in whom DHH was presumably provided by bone marrow niche cells. Moreover, the GLI inhibitor GANT61 or knockdown of GLI1/2 by shRNA caused antileukemic effects, including induction of apoptosis, reduced proliferation, and colony formation in AML cells, and a survival benefit in mice.
GLI expression is a negative prognostic factor and might represent a novel druggable target in AML.
To study the incidence and prognostic impact of mutations in DNA methyltransferase 3A (DNMT3A) in patients with acute myeloid leukemia.
A total of 489 patients with AML were examined for mutations in ...DNMT3A by direct sequencing. The prognostic impact of DNMT3A mutations was evaluated in the context of other clinical prognostic markers and genetic risk factors (cytogenetic risk group; mutations in NPM1, FLT3, CEBPA, IDH1, IDH2, MLL1, NRAS, WT1, and WT1 SNPrs16754; expression levels of BAALC, ERG, EVI1, MLL5, MN1, and WT1).
DNMT3A mutations were found in 87 (17.8%) of 489 patients with AML who were younger than 60 years of age. Patients with DNMT3A mutations were older, had higher WBC and platelet counts, more often had a normal karyotype and mutations in NPM1, FLT3, and IDH1 genes, and had higher MLL5 expression levels as compared with patients with wild-type DNMT3A. Mutations in DNMT3A independently predicted a shorter overall survival (OS; hazard ratio HR, 1.59; 95% CI, 1.15 to 2.21; P = .005) by multivariate analysis, but were not associated with relapse-free survival (RFS) or complete remission (CR) rate when the entire patient cohort was considered. In cytogenetically normal (CN) AML, 27.2% harbored DNMT3A mutations that independently predicted shorter OS (HR = 2.46; 95% CI, 1.58 to 3.83; P < .001) and lower CR rate (OR, 0.42; 95% CI, 0.21 to 0.84; P = .015), but not RFS (P = .32). Within patients with CN-AML, DNMT3A mutations had an unfavorable effect on OS, RFS, and CR rate in NPM1/FLT3-ITD high-risk but not in low-risk patients.
DNMT3A mutations are frequent in younger patients with AML and are associated with an unfavorable prognosis.
Acute myeloid leukemia (AML) represents a clonal disease of hematopoietic progenitors characterized by acquired heterogenous genetic changes that alter normal mechanisms of proliferation, ...self-renewal, and differentiation.1 Although 40% to 45% of patients younger than 65 years of age can be cured with current therapies, only 10% of older patients reach long-term survival.1 Because only very few novel AML drugs were approved in the past 2 decades, there is an urgent need to identify novel targets and therapeutic strategies to treat underserved AML patients. We report here that Axl, a member of the Tyro3, Axl, Mer receptor tyrosine kinase family,2-4 represents an independent prognostic marker and therapeutic target in AML. AML cells induce expression and secretion of the Axl ligand growth arrest–specific gene 6 (Gas6) by bone marrow–derived stromal cells (BMDSCs). Gas6 in turn mediates proliferation, survival, and chemoresistance of Axl-expressing AML cells. This Gas6-Axl paracrine axis between AML cells and BMDSCs establishes a chemoprotective tumor cell niche that can be abrogated by Axl-targeting approaches. Axl inhibition is active in FLT3-mutated and FLT3 wild-type AML, improves clinically relevant end points, and its efficacy depends on presence of Gas6 and Axl. Axl inhibition alone or in combination with chemotherapy might represent a novel therapeutic avenue for AML.
•Axl inhibition by BGB324 is active in FLT3-mutated and FLT3 wild-type AML, and presence of Axl and Gas6 are required for therapeutic efficacy.•AML cells educate BMDSCs to secrete Gas6, which mediates leukemia cell proliferation and therapy resistance.
To evaluate frequency, biologic features, and clinical relevance of RUNX1 mutations in acute myeloid leukemia (AML).
Diagnostic samples from 945 patients (age 18 to 60 years) were analyzed for RUNX1 ...mutations. In a subset of cases (n = 269), microarray gene expression analysis was performed.
Fifty-nine RUNX1 mutations were identified in 53 (5.6%) of 945 cases, predominantly in exons 3 (n = 11), 4 (n = 10), and 8 (n = 23). RUNX1 mutations clustered in the intermediate-risk cytogenetic group (46 of 640, 7.2%; cytogenetically normal, 34 of 538, 6.3%), whereas they were less frequent in adverse-risk cytogenetics (five of 109, 4.6%) and absent in core-binding-factor AML (0 of 77) and acute promyelocytic leukemia (0 of 61). RUNX1 mutations were associated with MLL-partial tandem duplications (P = .0007) and IDH1/IDH2 mutations (P = .03), inversely correlated with NPM1 (P < .0001), and in trend with CEBPA (P = .10) mutations. RUNX1 mutations were characterized by a distinct gene expression pattern; this RUNX1 mutation-derived signature was not exclusive for the mutation, but also included mostly adverse-risk AML eg, 7q-, -7, inv(3), or t(3;3). RUNX1 mutations predicted for resistance to chemotherapy (rates of refractory disease 30% and 19%, P = .047, for RUNX1-mutated and wild-type patients, respectively), as well as inferior event-free survival (EFS; P < .0001), relapse-free survival (RFS, P = .022), and overall survival (P = .051). In multivariable analysis, RUNX1 mutations were an independent prognostic marker for shorter EFS (P = .007). Explorative subgroup analysis revealed that allogeneic hematopoietic stem-cell transplantation had a favorable impact on RFS in RUNX1-mutated patients (P < .0001).
AML with RUNX1 mutations are characterized by distinct genetic properties and are associated with resistance to therapy and inferior outcome.
Mutations in the nucleophosmin 1 (NPM1) gene are considered a founder event in the pathogenesis of acute myeloid leukemia (AML). To address the role of clonal evolution in relapsed NPM1-mutated ...(NPM1mut) AML, we applied high-resolution, genome-wide, single-nucleotide polymorphism array profiling to detect copy number alterations (CNAs) and uniparental disomies (UPDs) and performed comprehensive gene mutation screening in 53 paired bone marrow/peripheral blood samples obtained at diagnosis and relapse. At diagnosis, 15 aberrations (CNAs, n = 10; UPDs, n = 5) were identified in 13 patients (25%), whereas at relapse, 56 genomic alterations (CNAs, n = 46; UPDs, n = 10) were detected in 29 patients (55%) indicating an increase in genomic complexity. Recurrent aberrations acquired at relapse included deletions affecting tumor suppressor genes (ETV6 n = 3, TP53 n = 2, NF1 n = 2, WT1 n = 3, FHIT n = 2) and homozygous FLT3 mutations acquired via UPD13q (n = 7). DNMT3A mutations (DNMT3Amut) showed the highest stability (97%). Persistence of DNMT3Amut in 5 patients who lost NPM1mut at relapse suggests that DNMT3Amut may precede NPM1mut in AML pathogenesis. Of note, all relapse samples shared at least 1 genetic aberration with the matched primary AML sample, implying common ancestral clones. In conclusion, our study reveals novel insights into clonal evolution in NPM1mut AML.
• Relapsed AML with NPM1 mutation is genetically related to the primary leukemia and characterized by an increase in high-risk aberrations.• DNMT3A mutations show the highest stability and thus may precede NPM1 mutations.
Mutations in the cohesin complex are novel, genetic lesions in acute myeloid leukemia (AML) that are not well characterized. In this study, we analyzed the frequency, clinical, and prognostic ...implications of mutations in STAG1, STAG2, SMC1A, SMC3, and RAD21, all members of the cohesin complex, in a cohort of 389 uniformly treated AML patients by next generation sequencing. We identified a total of 23 patients (5.9%) with somatic mutations in 1 of the cohesin genes. All gene mutations were mutually exclusive, and STAG1 (1.8%), STAG2 (1.3%), and SMC3 (1.3%) were most frequently mutated. Patients with any cohesin complex mutation had lower BAALC expression levels. We found a strong association between mutations affecting the cohesin complex and NPM1. Mutated allele frequencies were similar between NPM1 and cohesin gene mutations. Overall survival (OS), relapse-free survival (RFS), and complete remission rates (CR) were not influenced by the presence of cohesin mutations (OS: hazard ratio HR 0.98; 95% confidence interval CI, 0.56-1.72 P = .94; RFS: HR 0.7; 95% CI, 0.36-1.38 P = .3; CR: mutated 83% vs wild-type 76% P = .45). The cohesin complex presents a novel pathway affected by recurrent mutations in AML. This study is registered at www.clinicaltrials.gov as #NCT00209833.
•Mutations in genes of the cohesin complex are recurrent mutations in AML with a strong association with NPM1 mutations.•Cohesin gene mutations have no clear prognostic impact in AML patients.
To study the incidence and prognostic impact of mutations in Additional sex comb-like 1 (ASXL1) in a large cohort of patients with myelodysplastic syndrome (MDS).
Overall, 193 patients with MDS and ...65 healthy volunteers were examined for ASXL1 mutations by direct sequencing and for expression levels of ASXL1. The prognostic impact of ASXL1 mutation and expression levels was evaluated in the context of other clinical and molecular prognostic markers.
Mutations in ASXL1 occurred with a frequency of 20.7% in MDS (n = 40 of 193) with 70% (n = 28) of mutations being frameshift mutations and 30% (n = 12) being heterozygous point mutations leading to translational changes. ASXL1 mutations were correlated with an intermediate-risk karyotype (P = .002) but not with other clinical parameters. The presence of ASXL1 mutations was associated with a shorter overall survival for frameshift and point mutations combined (hazard ratio HR, 1.744; 95% CI, 1.08 to 2.82; P = .024) and for frameshift mutations only (HR, 2.06; 95% CI, 1.21 to 3.50; P = .008). ASXL1 frameshift mutations were associated with a reduced time to progression of acute myeloid leukemia (AML; HR 2.35; 95% CI, 1.17 to 4.74; P = .017). In multivariate analysis, when considering karyotype, transfusion dependence, and IDH1 mutation status, ASXL1 frameshift mutations remained an independent prognostic marker in MDS (overall survival: HR, 1.85; 95% CI, 1.03 to 3.34; P = .040; time to AML progression: HR, 2.39; 95% CI, 1.12 to 5.09; P = .024).
These results suggest that ASXL1 mutations are frequent molecular aberrations in MDS that predict an adverse prognostic outcome. Screening of patients for ASXL1 mutations might be useful for clinical risk stratification and treatment decisions in the future.
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