Characterization of therapy-related acute myeloid leukemia: increasing incidence and prognostic implications.

Studies of therapy-related AML (t-AML) are usually performed in selected cohorts and reliable incidence rates are lacking. In this study, we characterized, defined the incidence over time and studied prognostic implications in all t-AML patients diagnosed in Sweden between 1997 and 2015. Data were retrieved from nationwide population-based registries. In total, 6,779 AML patients were included in the study, of whom 686 (10%) had t-AML. The median age for t-AML was 71 years and 392 (57%) patients were females. During the study period, the incidence of t-AML almost doubled with a yearly increase in t-AML of 4.5% (95% confidence interval: 2.8%-6.2%), which contributed significantly to the general increase in AML incidence over the study period. t-AML solidly constituted over 10% of all AML cases during the later period of the study. Primary diagnoses with the largest increase in incidence and decrease in mortality rate during the study period (i.e., breast and prostate cancer) contributed significantly to the increased incidence of t-AML. In multivariable analysis, t-AML was associated with poorer outcome in cytogenetically intermediate- and adverse-risk cases but t-AML had no significant impact on outcome in favorable-risk AML, including core binding leukemias, acute promyelocytic leukemia and AML with mutated NPM1 without FLT3-ITD. We conclude that there is a strong increase in incidence in t-AML over time and that t-AML constitutes a successively larger proportion of the AML cases. Furthermore, we conclude that t-AML confers a poor prognosis in cytogenetically intermediate- and adverse-risk, but not in favorable-risk AML.

A risk score based on real-world data to predict early death in acute promyelocytic leukemia.

With increasingly effective treatments, early death (ED) has become the predominant reason for therapeutic failure in patients with acute promyelocytic leukemia (APL). To better prevent ED, patients with high-risk of ED must be identified. Our aim was to develop a score that predicts the risk of ED in a real-life setting. We used APL patients in the populationbased Swedish AML Registry (n=301) and a Portuguese hospital-based registry (n=129) as training and validation cohorts, respectively. The cohorts were comparable with respect to age (median, 54 and 53 years) and ED rate (19.6% and 18.6%). The score was developed by logistic regression analyses, risk-per-quantile assessment and scoring based on ridge regression coefficients from multivariable penalized logistic regression analysis. White blood cell count, platelet count and age were selected by this approach as the most significant variables for predicting ED. The score identified low-, high- and very high-risk patients with ED risks of 4.8%, 20.2% and 50.9% respectively in the training cohort and with 6.7%, 25.0% and 36.0% as corresponding values for the validation cohort. The score identified an increased risk of ED already at sub-normal and normal white blood cell counts and, consequently, it was better at predicting ED risk than the Sanz score (AUROC 0.77 vs. 0.64). In summary, we here present an externally validated and population-based risk score to predict ED risk in a real-world setting, identifying patients with the most urgent need of aggressive ED prevention. The results also suggest that increased vigilance for ED is already necessary at sub-normal/normal white blood cell counts.

Is there an impact of measurable residual disease as assessed by multiparameter flow cytometry on survival of AML patients treated in clinical practice? A population-based study.

The Swedish national guidelines for treatment of acute myeloid leukemia (AML) recommend analysis of measurable residual disease (MRD) by multiparameter flow cytometry (MFC) in bone marrow in the routine clinical setting. The Swedish AML registry contains such MRD data in AML patients diagnosed 2011-2019. Of 327 patients with AML (non-APL) with MRD-results reported in complete remission after two courses of intensive chemotherapy 229 were MRD-negative (70%), as defined by <0.1% cells with leukemia-associated immunophenotype in the bone marrow. MRD-results were reported to clinicians in real time. Multivariate statistical analysis adjusted for known established risk factors did not indicate an association between MFC-MRD and overall survival (HR: 1.00 [95% CI 0.61, 1.63]) with a median follow-up of 2.7 years. Knowledge of the importance of MRD status by clinicians and individualized decisions could have ameliorated the effects of MRD as an independent prognostic factor of overall survival.

Clinical and genomic characterization of patients diagnosed with the provisional entity acute myeloid leukemia with BCR-ABL1, a Swedish population-based study.

Acute myeloid leukemia (AML) with t(9;22)(q34;q11), also known as AML with BCR-ABL1, is a rare, provisional entity in the WHO 2016 classification and is considered a high-risk disease according to the European LeukemiaNet 2017 risk stratification. We here present a retrospective, population-based study of this disease entity from the Swedish Acute Leukemia Registry. By strict clinical inclusion criteria we aimed to identify genetic markers further distinguishing AML with t(9;22) as a separate entity. Twenty-five patients were identified and next-generation sequencing using a 54-gene panel was performed in 21 cases. Interestingly, no mutations were found in NPM1, FLT3, or DNMT3A, three frequently mutated genes in AML. Instead, RUNX1 was the most commonly mutated gene, with aberrations present in 38% of the cases compared to around 10% in de novo AML. Additional mutations were identified in genes involved in RNA splicing (SRSF2, SF3B1) and chromatin regulation (ASXL1, STAG2, BCOR, BCORL1). Less frequently, mutations were found in IDH2, NRAS, TET2, and TP53. The mutational landscape exhibited a similar pattern as recently described in patients with chronic myeloid leukemia (CML) in myeloid blast crisis (BC). Despite the concomitant presence of BCR-ABL1 and RUNX1 mutations in our cohort, both features of high-risk AML, the RUNX1-mutated cases showed a superior overall survival compared to RUNX1 wildtype cases. Our results suggest that the molecular characteristics of AML with t(9;22)/BCR-ABL1 and CML in myeloid BC are similar and do not support a distinction of the two disease entities based on their underlying molecular alterations.

The prognostic impact of FLT3-ITD and NPM1 mutation in adult AML is age-dependent in the population-based setting.

In acute myeloid leukemia (AML) FLT3 internal tandem duplication (ITD) and nucleophosmin 1 (NPM1) mutations provide prognostic information with clinical relevance through choice of treatment, but the effect of age and sex on these molecular markers has not been evaluated. The Swedish AML Registry contains data on FLT3-ITD and NPM1 mutations dating to 2007, and 1570 adult patients younger than 75 years, excluding acute promyelocytic leukemia, had molecular results reported. Females more often had FLT3ITD and/or NPM1mut (FLT3ITD: female, 29%; male, 22% [P = .0015]; NPM1mut: female, 36%; male, 27% [P = .0001]), and more males were double negative (female, 53%; male, 64%; P < .0001). Patients with FLT3ITD were younger than those without (59 vs 62 years; P = .023), in contrast to patients with NPM1mut (62 vs 60 years; P = .059). Interestingly, their prognostic effect had a strong dependence on age: FLT3ITD indicated poor survival in younger patients (<60 years; P = .00003), but had no effect in older patients (60-74 years; P = .5), whereas NPM1mut indicated better survival in older patients (P = .00002), but not in younger patients (P = .95). In FLT3ITD/NPM1mut patients, the survival was less dependent on age than in the other molecular subsets. These findings are likely to have clinical relevance for risk grouping, study design, and choice of therapy.

Secondary Acute Myeloid Leukemia and the Role of Allogeneic Stem Cell Transplantation in a Population-Based Setting.

Secondary AML (s-AML), including AML with an antecedent hematologic disorder (AHD-AML) and therapy-related AML (t-AML), constitutes a large proportion of patients with AML and is considered to confer a dismal prognosis. The role of allogeneic hematopoietic cell transplantation (HCT) in patients with s-AML and the extent to which HCT is performed in these patients has been little studied to date. We used the population-based Swedish AML Registry comprising 3337 intensively treated adult patients over a 17-year period to study the role of HCT within the group of patients with s-AML as well as compared with patients with de novo AML. HCT was performed in 576 patients (22%) with de novo AML, in 74 patients (17%) with AHD-AML, and in 57 patients (20%) with t-AML. At 5 years after diagnosis, there were no survivors among patients with previous myeloproliferative neoplasms who did not undergo HCT, and corresponding survival for patients with antecedent myelodysplastic syndromes and t-AML was and 2% and 4%, respectively. HCT was compared with chemotherapy consolidation in s-AML using 3 models: (1) a 200-day landmark analysis, in which HCT was favorable compared with conventional consolidation (P = .04, log-rank test); (2) a multivariable Cox regression with HCT as a time-dependent variable, in which the hazard ratio for mortality was 0.73 (95% confidence interval, 0.64 to 0.83) for HCT and favored HCT in all subgroups; and (3) a propensity score matching analysis, in which the 5-year overall survival (OS) and relapse-free survival in patients with s-AML in first complete remission (CR1) was 48% and 43%, respectively, for patients undergoing HCT versus 20% and 21%, respectively, for those receiving chemotherapy consolidation (P = .01 and .02, respectively, log-rank test). Our observational data suggest that HCT improves survival and offers the only realistic curative treatment option in patients with s-AML.

Anthracycline-based consolidation may determine outcome of post-consolidation immunotherapy in AML.

Consolidation chemotherapy in acute myeloid leukemia (AML) aims at eradicating residual leukemic cells and mostly comprises high-dose cytarabine with or without the addition of anthracyclines, including daunorubicin. Immunogenic cell death (ICD) may contribute to the efficacy of anthracyclines in solid cancer, but the impact of ICD in AML is only partly explored. We assessed aspects of ICD, as reflected by calreticulin expression, in primary human AML blasts and observed induction of surface calreticulin upon exposure to daunorubicin but not to cytarabine. We next assessed immune phenotypes in AML patients in complete remission (CR), following consolidation chemotherapy with or without anthracyclines. These patients subsequently received immunotherapy with histamine dihydrochloride (HDC) and IL-2. Patients who had received anthracyclines for consolidation showed enhanced frequencies of CD8+ TEM cells in blood along with improved survival. We propose that the choice of consolidation therapy prior to AML immunotherapy may determine clinical outcome.

NOX2-dependent immunosuppression in chronic myelomonocytic leukemia.

Chronic myelomonocytic leukemia (CMML) is a myeloproliferative and myelodysplastic neoplasm with few treatment options and dismal prognosis. The role of natural killer (NK) cells and other antileukemic lymphocytes in CMML is largely unknown. We aimed to provide insight into the mechanisms of immune evasion in CMML with a focus on immunosuppressive reactive oxygen species (ROS) formed by the myeloid cell NADPH oxidase-2 (NOX2). The dominant population of primary human CMML cells was found to express membrane-bound NOX2 and to release ROS, which, in turn, triggered extensive PARP-1-dependent cell death in cocultured NK cells, CD8+ T effector memory cells, and CD8+ T effector cells. Inhibitors of ROS formation and scavengers of extracellular ROS prevented CMML cell-induced lymphocyte death and facilitated NK cell degranulation toward Ab-coated, primary CMML cells. In patients with CMML, elevation of immature cell counts (CD34+) in blood was associated with reduced expression of several NK cell-activating receptors. We propose that CMML cells may use extracellular ROS as a targetable mechanism of immune escape.

Incidence and prognostic significance of isolated trisomies in adult acute myeloid leukemia: A population-based study from the Swedish AML registry.

OBJECTIVES AND METHODS: To ascertain the incidence/clinical implications of isolated autosomal trisomies in adult acute myeloid leukemia (AML), all such cases were retrieved from the Swedish AML Registry. RESULTS: Of the 3179 cytogenetically informative AMLs diagnosed January 1997-May 2015, 246 (7.7%) had isolated trisomies. The frequency increased by age (2.4% at age 18-60 years vs. 23% at >60 years; P<.0001); the median age was 69 years. The five most common were +8 (4.0%), +13 (0.9%), +11 (0.8%), +21 (0.7%), and +4 (0.5%). Age and gender, types of AML and treatment, and complete remission and early death rates did not differ between the single trisomy and the intermediate risk (IR) groups or among cases with isolated gains of chromosomes 4, 8, 11, 13, or 21. The overall survival (OS) was similar in the single trisomy (median 1.6 years) and IR groups (1.7 years; P=.251). The OS differed among the most frequent isolated trisomies; the median OS was 2.5 years for +4, 1.9 years for +21, 1.5 years for +8, 1.1 years for +11, and 0.8 years for +13 (P=.013). CONCLUSION: AML with single trisomies, with the exception of +13, should be grouped as IR.

Prognostic significance of high hyperdiploid and triploid/tetraploid adult acute myeloid leukemia.

To ascertain the clinical implications of high hyperdiploid (HH; 49-65 chromosomes) and triploid/tetraploid (TT; >65 chromosomes) adult acute myeloid leukemia (AML), all such cases were retrieved from the Swedish AML Registry. Of the 3,654 cytogenetically informative cases diagnosed between January 1997 and May 2014, 68 (1.9%) were HH (n = 50)/TT (n = 18). Patients with HH/TT were older than those with intermediate risk (IR) AML (median 71 years vs. 67 years; P = 0.042) and less often had de novo AML (63% vs. 79%; P = 0.004); no such differences were observed between HH/TT and complex karyotype (CK) AML. The overall survival (OS) was similar between patients with HH/TT and CK AML (median 0.9 years vs. 0.6 years; P = 0.082), whereas OS was significantly longer (median 1.6 years; P = 0.028) for IR AML. The OS was shorter for cases with HH than with TT (median 0.6 years vs. 1.4 years; P = 0.032) and for HH/TT AMLs with adverse abnormalities (median 0.8 years vs. 1.1 years; P = 0.044). In conclusion, HH/TT AML is associated with a poor outcome, but chromosome numbers >65 and absence of adverse aberrations seem to translate into a more favorable prognosis. Thus, HH/TT AMLs are clinically heterogeneous and should not automatically be grouped as high risk.

Characterization and prognostic features of secondary acute myeloid leukemia in a population-based setting: a report from the Swedish Acute Leukemia Registry.

Patients with secondary acute myeloid leukemia (AML) often escape inclusion in clinical trials and thus, population-based studies are crucial for its accurate characterization. In this first large population-based study on secondary AML, we studied AML with an antecedent hematological disease (AHD-AML) or therapy-related AML (t-AML) in the population-based Swedish Acute Leukemia Registry. The study included 3,363 adult patients of which 2,474 (73.6%) had de novo AML, 630 (18.7%) AHD-AML, and 259 (7.7%) t-AML. Secondary AML differed significantly compared to de novo AML with respect to age, gender, and cytogenetic risk. Complete remission (CR) rates were significantly lower but early death rates similar in secondary AML. In a multivariable analysis, AHD-AML (HR 1.51; 95% CI 1.26-1.79) and t-AML (1.72; 1.38-2.15) were independent risk factors for poor survival. The negative impact of AHD-AML and t-AML on survival was highly age dependent with a considerable impact in younger patients, but without independent prognostic value in the elderly. Although patients with secondary leukemia did poorly with intensive treatment, early death rates and survival were significantly worse with palliative treatment. We conclude that secondary AML in a population-based setting has a striking impact on survival in younger AML patients, whereas it lacks prognostic value among the elderly patients.

Failure matters: unsuccessful cytogenetics and unperformed cytogenetics are associated with a poor prognosis in a population-based series of acute myeloid leukaemia.

Unsuccessful cytogenetics (UC) in patients with acute myeloid leukaemia (AML) treated on different SWOG trials was recently reported to be associated with increased age and dismal outcome. To ascertain whether this holds true also in unselected patients with AML, we retrieved all cytogenetic reports in cases from the population-based Swedish AML Registry. Between 1997 and 2006, 1737 patients below 80 yr of age without myelosarcoma or acute promyelocytic leukaemia received intensive treatment. The frequencies of UC and unperformed cytogenetics (UPC) were 2.1% and 20%, respectively. The early death rates differed between the cytogenetic subgroups (P = 0.006) with the highest rates in patients with UC (14%) and UPC (12%) followed by high-risk (HR) AML, intermediate risk (IR) and standard risk (SR) cases successfully karyotyped (8.6%, 5.9%, and 5.8%, respectively). The complete remission rate was lower in UC and UPC and HR compared with the other risk groups (P < 0.001). The overall five-year survival rates were 25% for UC and 22% for UPC, whereas the corresponding frequencies for SR, IR and HR AML patients without UC and UPC were 64%, 31% and 15%, respectively. In conclusion, lack of cytogenetic data translates into a poor prognosis.

Allelic methylation levels of the noncoding VTRNA2-1 located on chromosome 5q31.1 predict outcome in AML.

Deletions of chromosome 5q are associated with poor outcomes in acute myeloid leukemia (AML) suggesting the presence of tumor suppressor(s) at the locus. However, definitive identification of putative tumor suppressor genes remains controversial. Here we show that a 106-nucleotide noncoding RNA vault RNA2-1 (vtRNA2-1), previously misannotated as miR886, could potentially play a role in the biology and prognosis of AML. vtRNA2-1 is transcribed by polymerase III and is monoallelically methylated in 75% of healthy individuals whereas the remaining 25% of the population have biallelic hypomethylation. AML patients without methylation of VTRNA2-1 have a considerably better outcome than those with monoallelic or biallelic methylation (n = 101, P = .001). We show that methylation is inversely correlated with vtRNA2-1 expression, and that 5-azanucleosides induce vtRNA2-1 and down-regulate the phosphorylated RNA-dependent protein kinase (pPKR), whose activity has been shown to be modulated by vtRNA2-1. Because pPKR promotes cell survival in AML, the data are consistent with vtRNA2-1 being a tumor suppressor in AML. This is the first study to show that vtRNA2-1 might play a significant role in AML, that it is either mono- or biallelically expressed in the blood cells of healthy individuals, and that its methylation state predicts outcome in AML.

Clinical effect of increasing doses of lenalidomide in high-risk myelodysplastic syndrome and acute myeloid leukemia with chromosome 5 abnormalities.

BACKGROUND: Patients with chromosome 5 abnormalities and high-risk myelodysplastic syndromes or acute myeloid leukemia have a poor outcome. We hypothesized that increasing doses of lenalidomide may benefit this group of patients by inhibiting the tumor clone, as assessed by fluorescence in situ hybridization for del(5q31). DESIGN AND METHODS: Twenty-eight patients at diagnosis or with relapsed disease and not eligible for standard therapy (16 with acute myeloid leukemia, 12 with intermediate-risk 2 or high-risk myelodysplastic syndrome) were enrolled in this prospective phase II multicenter trial and treated with lenalidomide up to 30 mg daily for 16 weeks. Three patients had isolated del(5q), six had del(5q) plus one additional aberration, 14 had del(5q) and a complex karyotype, four had monosomy 5, and one had del(5q) identified by fluorescence in situ hybridization only. RESULTS: Major and minor cytogenetic responses, assessed by fluorescence in situ hybridization, were achieved in 5/26 (19%) and 2/26 (8%) patients, respectively, who received one or more dose of lenalidomide, while two patients achieved only a bone marrow response. Nine of all 26 patients (35%) and nine of the ten who completed the 16 weeks of trial responded to treatment. Using the International Working Group criteria for acute myeloid leukemia and myelodysplastic syndrome the overall response rate in treated patients with acute myeloid leukemia was 20% (3/15), while that for patients with myelodysplastic syndrome was 36% (4/11). Seven patients stopped therapy due to progressive disease and nine because of complications, most of which were disease-related. Response rates were similar in patients with isolated del(5q) and in those with additional aberrations. Interestingly, patients with TP53 mutations responded less well than those without mutations (2/13 versus 5/9, respectively; P=0.047). No responses were observed among 11 cases with deleterious TP53 mutations. CONCLUSIONS: Our data support a role for higher doses of lenalidomide in poor prognosis patients with myelodysplastic syndrome and acute myeloid leukemia with deletion 5q. (Clinicaltrials.gov identifier NCT00761449).