Purpose: This multicenter, randomized, open-label, phase III trial compared the efficacy and safety of decitabine with treatment choice (TC) in older patients with newly diagnosed acute myeloid leukemia (AML) and poor- or intermediate-risk cytogenetics. Patients and Methods: Patients (N = 485) age ≥ 65 years were randomly assigned 1:1 to receive decitabine 20 mg/m² per day as a 1-hour intravenous infusion for five consecutive days every 4 weeks or TC (supportive care or cytarabine 20 mg/m² per day as a subcutaneous injection for 10 consecutive days every 4 weeks). The primary end point was overall survival (OS); the secondary end point was the complete remission (CR) rate plus the CR rate without platelet recovery (CRp). Adverse events (AEs) were recorded. Results: The primary analysis with 396 deaths (81.6%) showed a nonsignificant increase in median OS with decitabine (7.7 months; 95% CI, 6.2 to 9.2) versus TC (5.0 months; 95% CI, 4.3 to 6.3; P = .108; hazard ratio [HR], 0.85; 95% CI, 0.69 to 1.04). An unplanned analysis with 446 deaths (92%) indicated the same median OS (HR, 0.82; 95% CI, 0.68 to 0.99; nominal P = .037). The CR rate plus CRp was 17.8% with decitabine versus 7.8% with TC (odds ratio, 2.5; 95% CI, 1.4 to 4.8; P = .001). AEs were similar for decitabine and cytarabine, although patients received a median of four cycles of decitabine versus two cycles of TC. The most common drug-related AEs with decitabine were thrombocytopenia (27%) and neutropenia (24%). Conclusion: In older patients with AML, decitabine improved response rates compared with standard therapies without major differences in safety. An unplanned survival analysis showed a benefit for decitabine, which was not observed at the time of the primary analysis.

Somatic mutation of the AML1/RUNX1(RUNX1) gene is seen in acute myeloid leukemia (AML) M0 subtype and in AML transformed from myelodysplastic syndrome, but the impact of this gene mutation on survival in AML patients remains unclear. In this study, we sought to determine the clinical implications of RUNX1 mutations in 470 adult patients with de novo non-M3 AML. Sixty-three distinct RUNX1 mutations were identified in 62 persons (13.2%); 32 were in N-terminal and 31, C-terminal. The RUNX1 mutation was closely associated with male sex, older age, lower lactic dehydrogenase value, French-American-British M0/M1 subtypes, and expression of HLA-DR and CD34, but inversely correlated with CD33, CD15, CD19, and CD56 expression. Furthermore, the mutation was positively associated with MLL/PTD but negatively associated with CEBPA and NPM1 mutations. AML patients with RUNX1 mutations had a significantly lower complete remission rate and shorter disease-free and overall survival than those without the mutation. Multivariate analysis demonstrated that RUNX1 mutation was an independent poor prognostic factor for overall survival. Sequential analysis in 133 patients revealed that none acquired novel RUNX1 mutations during clinical courses. Our findings provide evidence that RUNX1 mutations are associated with distinct biologic and clinical characteristics and poor prognosis in patients with de novo AML.

The studies concerning clinical implications of TET2 mutation in patients with primary acute myeloid leukemia (AML) are scarce. We analyzed TET2 mutation in 486 adult patients with primary AML. TET2 mutation occurred in 13.2% of our patients and was closely associated with older age, higher white blood cell and blast counts, lower platelet numbers, normal karyotype, intermediate-risk cytogenetics, isolated trisomy 8, NPM1 mutation, and ASXL1 mutation but mutually exclusive with IDH mutation. TET2 mutation is an unfavorable prognostic factor in patients with intermediate-risk cytogenetics, and its negative impact was further enhanced when the mutation was combined with FLT3-ITD, NPM1-wild, or unfavorable genotypes (other than NPM1⁺/FLT3-ITD⁻ or CEBPA⁺). A scoring system integrating TET2 mutation with FLT3-ITD, NPM1, and CEBPA mutations could well separate AML patients with intermediate-risk cytogenetics into 4 groups with different prognoses (P < .0001). Sequential analysis revealed that TET2 mutation detected at diagnosis was frequently lost at relapse; rarely, the mutation was acquired at relapse in those without TET2 mutation at diagnosis. In conclusion, TET2 mutation is associated with poor prognosis in AML patients with intermediate-risk cytogenetics, especially when it is combined with other adverse molecular markers. TET2 mutation appeared to be unstable during disease evolution.

DNMT3A mutations are associated with poor prognosis in acute myeloid leukemia (AML), but the stability of this mutation during the clinical course remains unclear. In the present study of 500 patients with de novo AML, DNMT3A mutations were identified in 14% of total patients and in 22.9% of AML patients with normal karyotype. DNMT3A mutations were positively associated with older age, higher WBC and platelet counts, intermediate-risk and normal cytogenetics, FLT3 internal tandem duplication, and NPM1, PTPN11, and IDH2 mutations, but were negatively associated with CEBPA mutations. Multivariate analysis demonstrated that the DNMT3A mutation was an independent poor prognostic factor for overall survival and relapse-free survival in total patients and also in normokaryotype group. A scoring system incorporating the DNMT3A mutation and 8 other prognostic factors, including age, WBC count, cytogenetics, and gene mutations, into survival analysis was very useful in stratifying AML patients into different prognostic groups (P < .001). Sequential study of 138 patients during the clinical course showed that DNMT3A mutations were stable during AML evolution. In conclusion, DNMT3A mutations are associated with distinct clinical and biologic features and poor prognosis in de novo AML patients. Furthermore, the DNMT3A mutation may be a potential biomarker for monitoring of minimal residual disease.

Arsenic has played a key medicinal role against a variety of ailments for several millennia, but during the past century its prominence has been displaced by modern therapeutics. Recently, attention has been drawn to arsenic by its dramatic clinical efficacy against acute promyelocytic leukemia. Although toxic reactive oxygen species (ROS) induced in cancer cells exposed to arsenic could mediate cancer cell death, how arsenic induces ROS remains undefined. Through the use of gene expression profiling, interference RNA, and genetically engineered cells, we report here that NADPH oxidase, an enzyme complex required for the normal antibacterial function of white blood cells, is the main target of arsenic-induced ROS production. Because NADPH oxidase enzyme activity can also be stimulated by phorbol myristate acetate, a synergism between arsenic and the clinically used phorbol myristate acetate analog, bryostatin 1, through enhanced ROS production can be expected. We show that this synergism exists, and that the use of very low doses of both arsenic and bryostatin 1 can effectively kill leukemic cells. Our findings pinpoint the arsenic target of ROS production and provide a conceptual basis for an anticancer regimen.

Mutations in the additional sex comb-like 1 (ASXL1) gene were recently shown in various myeloid malignancies, but they have not been comprehensively investigated in acute myeloid leukemia (AML). In this study, we analyzed ASXL1 mutations in exon 12 in 501 adults with de novo AML. ASXL1 mutations were detected in 54 patients (10.8%), 8.9% among those with normal karyotype and 12.9% among those with abnormal cytogenetics. The mutation was closely associated with older age, male sex, isolated trisomy 8, RUNX1 mutation, and expression of human leukocyte antigen–DR and CD34, but inversely associated with t(15;17), complex cytogenetics, FLT3–internal tandem duplication, NPM1 mutations, WT1 mutations, and expression of CD33 and CD15. Patients with ASXL1 mutations had a shorter overall survival than patients without, but the mutation was not an independent adverse prognostic factor in multivariate analysis. Sequential analyses showed that the original ASXL1 mutations were lost at relapse and/or refractory status in 2 of the 6 relapsed ASXL1-mutated patients studied, whereas 2 of the 109 ASXL1-wild patients acquired a novel ASXL1 mutation at relapse. In conclusion, AML bearing ASXL1 mutations showed distinct clinical and biological features. The ASXL1 mutation status can change during disease evolution in a few patients.