Phase II evaluation of an intensified induction therapy with standard daunomycin and cytarabine followed by high dose cytarabine for adults with previously untreated acute myeloid leukemia: a Southwest Oncology Group study (SWOG-9500)

Comprehensive molecular and clinical characterization of NUP98 fusions in pediatric acute myeloid leukemia

NUP98 fusions comprise a family of rare recurrent alterations in AML, associated with adverse outcomes. In order to define the underlying biology and clinical implications of this family of fusions, we performed comprehensive transcriptome, epigenome, and immunophenotypic profiling of 2,235 children and young adults with AML and identified 160 NUP98 rearrangements (7.2%), including 108 NUP98-NSD1 (4.8%), 32 NUP98-KDM5A (1.4%) and 20 NUP98-X cases (0.9%) with 13 different fusion partners. Fusion partners defined disease characteristics and biology; patients with NUP98-NSD1 or NUP98-KDM5A had distinct immunophenotypic, transcriptomic, and epigenomic profiles. Unlike the two most prevalent NUP98 fusions, NUP98-X variants are typically not cryptic. Furthermore, NUP98-X cases are associated with WT1 mutations, and have epigenomic profiles that resemble either NUP98-NSD1 or NUP98-KDM5A. Cooperating FLT3-ITD and WT1 mutations define NUP98-NSD1, and chromosome 13 aberrations are highly enriched in NUP98-KDM5A. Importantly, we demonstrate that NUP98 fusions portend dismal overall survival, with the noteworthy exception of patients bearing abnormal chromosome 13 (clinicaltrials gov. Identifiers: NCT00002798, NCT00070174, NCT00372593, NCT01371981).

Verification of prognostic expression biomarkers is improved by examining enriched leukemic blasts rather than mononuclear cells from acute myeloid leukemia patients

BACKGROUND

Studies have not systematically compared the ability to verify performance of prognostic transcripts in paired bulk mononuclear cells versus viable CD34-expressing leukemic blasts from patients with acute myeloid leukemia. We hypothesized that examining the homogenous leukemic blasts will yield different biological information and may improve prognostic performance of expression biomarkers.

METHODS

To assess the impact of cellular heterogeneity on expression biomarkers in acute myeloid leukemia, we systematically examined paired mononuclear cells and viable CD34-expressing leukemic blasts from SWOG diagnostic specimens. After enrichment, patients were assigned into discovery and validation cohorts based on availability of extracted RNA. Analyses of RNA sequencing data examined how enrichment impacted differentially expressed genes associated with pre-analytic variables, patient characteristics, and clinical outcomes.

RESULTS

Blast enrichment yielded significantly different expression profiles and biological pathways associated with clinical characteristics (e.g., cytogenetics). Although numerous differentially expressed genes were associated with clinical outcomes, most lost their prognostic significance in the mononuclear cells and blasts after adjusting for age and ELN risk, with only 11 genes remaining significant for overall survival in both cell populations (CEP70, COMMD7, DNMT3B, ECE1, LNX2, NEGR1, PIK3C2B, SEMA4D, SMAD2, TAF8, ZNF444). To examine the impact of enrichment on biomarker verification, these 11 candidate biomarkers were examined by quantitative RT/PCR in the validation cohort. After adjusting for ELN risk and age, expression of 4 genes (CEP70, DNMT3B, ECE1, and PIK3CB) remained significantly associated with overall survival in the blasts, while none met statistical significance in mononuclear cells.

CONCLUSIONS

This study provides insights into biological information gained/lost by examining viable CD34-expressing leukemic blasts versus mononuclear cells from the same patient and shows an improved verification rate for expression biomarkers in blasts.

Daunorubicin and cytarabine for certain types of poor-prognosis acute myeloid leukemia: a systematic literature review

INTRODUCTION

Induction chemotherapy based on anthracyclines and cytarabine (Ara-C) combination remains the standard of care for acute myeloid leukemia (AML) patients who are considered candidate for intensive and curative approaches. However, the toxicity of this regimen is high, with disappointing clinical outcomes among the so-called poor-prognosis AML subsets, which generally refer to patients with adverse cytogenetic risk, secondary AML including therapy-related AML, poor-prognosis mutations, especially FLT3-ITD, and relapse/refractory AML. Areas covered: To the best of our knowledge, the role and efficacy of 7 + 3 schedules containing daunorubicin (DNR) and Ara-C for certain types of poor-prognosis AML has not been systematically assessed. A critical approach to the role of DNR and Ara-C induction could be relevant to establish which patients should be enrolled in clinical trials using novel therapies. Expert commentary: In this regard, a recent randomized clinical trial (RCT) showed improved results in older patients with sAML or high-risk cytogenetics who received CPX-351 compared with standard 7 + 3 combination. We perform a systematic literature review to analyze the clinical outcomes reported with DNR plus Ara-C regimens in adult patients with poor-prognosis AML, the use of liposomal formulations of DNR and Ara-C and the RCTs which compared standard 7 + 3 with the addition of a third drug.

Impact of Specimen Heterogeneity on Biomarkers in Repository Samples from Patients with Acute Myeloid Leukemia: A SWOG Report

INTRODUCTION

Current prognostic models for acute myeloid leukemia (AML) are inconsistent at predicting clinical outcomes for individual patients. Variability in the quality of specimens utilized for biomarker discovery and validation may contribute to this prognostic inconsistency.

METHODS

We evaluated the impact of sample heterogeneity on prognostic biomarkers and methods to mitigate any adverse effects of this heterogeneity in 240 cryopreserved bone marrow and peripheral blood specimens from AML patients enrolled on SWOG (Southwest Oncology Group) trials.

RESULTS

Cryopreserved samples displayed a broad range in viability (37% with viabilities ≤60%) and nonleukemic cell contamination (13% with lymphocyte percentages >20%). Specimen viability was impacted by transport time, AML immunophenotype, and, potentially, patients' age. The viability and cellular heterogeneity in unsorted samples significantly altered biomarker results. Enriching for viable AML blasts improved the RNA quality from specimens with poor viability and refined results for both DNA and RNA biomarkers. For example, FLT3-ITD allelic ratio, which is currently utilized to risk-stratify AML patients, was on average 1.49-fold higher in the viable AML blasts than in the unsorted specimens.

CONCLUSION

To our knowledge, this is the first study to provide evidence that using cryopreserved specimens can introduce uncontrollable variables that may impact biomarker results and enrichment for viable AML blasts may mitigate this impact.

Initial Diagnostic Workup of Acute Leukemia: Guideline From the College of American Pathologists and the American Society of Hematology

CONTEXT

- A complete diagnosis of acute leukemia requires knowledge of clinical information combined with morphologic evaluation, immunophenotyping and karyotype analysis, and often, molecular genetic testing. Although many aspects of the workup for acute leukemia are well accepted, few guidelines have addressed the different aspects of the diagnostic evaluation of samples from patients suspected to have acute leukemia.

OBJECTIVE

- To develop a guideline for treating physicians and pathologists involved in the diagnostic and prognostic evaluation of new acute leukemia samples, including acute lymphoblastic leukemia, acute myeloid leukemia, and acute leukemias of ambiguous lineage.

DESIGN

- The College of American Pathologists and the American Society of Hematology convened a panel of experts in hematology and hematopathology to develop recommendations. A systematic evidence review was conducted to address 6 key questions. Recommendations were derived from strength of evidence, feedback received during the public comment period, and expert panel consensus.

RESULTS

- Twenty-seven guideline statements were established, which ranged from recommendations on what clinical and laboratory information should be available as part of the diagnostic and prognostic evaluation of acute leukemia samples to what types of testing should be performed routinely, with recommendations on where such testing should be performed and how the results should be reported.

CONCLUSIONS

- The guideline provides a framework for the multiple steps, including laboratory testing, in the evaluation of acute leukemia samples. Some aspects of the guideline, especially molecular genetic testing in acute leukemia, are rapidly changing with new supportive literature, which will require on-going updates for the guideline to remain relevant.

Prognostic significance of NPM1 mutations in the absence of FLT3-internal tandem duplication in older patients with acute myeloid leukemia: a SWOG and UK National Cancer Research Institute/Medical Research Council report

PURPOSE

Younger patients with acute myeloid leukemia (AML) harboring NPM1 mutations without FLT3-internal tandem duplications (ITDs; NPM1-positive/FLT3-ITD-negative genotype) are classified as better risk; however, it remains uncertain whether this favorable classification can be applied to older patients with AML with this genotype. Therefore, we examined the impact of age on the prognostic significance of NPM1-positive/FLT3-ITD-negative status in older patients with AML.

PATIENTS AND METHODS

Patients with AML age ≥ 55 years treated with intensive chemotherapy as part of Southwest Oncology Group (SWOG) and UK National Cancer Research Institute/Medical Research Council (NCRI/MRC) trials were evaluated. A comprehensive analysis first examined 156 patients treated in SWOG trials. Validation analyses then examined 1,258 patients treated in MRC/NCRI trials. Univariable and multivariable analyses were used to determine the impact of age on the prognostic significance of NPM1 mutations, FLT3-ITDs, and the NPM1-positive/FLT3-ITD-negative genotype.

RESULTS

Patients with AML age 55 to 65 years with NPM1-positive/FLT3-ITD-negative genotype treated in SWOG trials had a significantly improved 2-year overall survival (OS) as compared with those without this genotype (70% v 32%; P < .001). Moreover, patients age 55 to 65 years with NPM1-positive/FLT3-ITD-negative genotype had a significantly improved 2-year OS as compared with those age > 65 years with this genotype (70% v 27%; P < .001); any potential survival benefit of this genotype in patients age > 65 years was marginal (27% v 16%; P = .33). In multivariable analysis, NPM1-positive/FLT3-ITD-negative genotype remained independently associated with an improved OS in patients age 55 to 65 years (P = .002) but not in those age > 65 years (P = .82). These results were confirmed in validation analyses examining the NCRI/MRC patients.

CONCLUSION

NPM1-positive/FLT3-ITD-negative genotype remains a relatively favorable prognostic factor for patients with AML age 55 to 65 years but not in those age > 65 years.

Outcome of adolescents and young adults with acute myeloid leukemia treated on COG trials compared to CALGB and SWOG trials

BACKGROUND

A retrospective meta-analysis of adolescents and young adults (AYAs) with acute myeloid leukemia (AML) was performed to determine if differences in outcome exist following treatment on pediatric versus adult oncology treatment regimens.

METHODS

Outcomes were compared of 517 AYAs with AML aged 16 to 21 years who were treated on Children's Oncology Group (COG), Cancer and Leukemia Group B (CALGB), and Southwest Oncology Group (SWOG) frontline AML trials from 1986 to 2008.

RESULTS

There was a significant age difference between AYA cohorts in the COG, CALGB, and SWOG trials (median, 17.2 versus 20.1 versus 19.8 years, P < .001). The 10-year event-free survival of the COG cohort was superior to the combined adult cohorts (38% ± 6% versus 23% ± 6%, log-rank P = .006) as was overall survival (45% ± 6% versus 34% ± 7%), with a 10-year estimate comparison of P = .026. However, the younger age of the COG cohort is confounding, with all patients aged 16 to 18 years doing better than those aged 19 to 21 years. Although the 10-year relapse rate was lower for the COG patients (29% ± 6% versus 57% ± 8%, Gray's P < .001), this was offset by a higher postremission treatment-related mortality of 26% ± 6% versus 12% ± 6% (Gray's P < .001). Significant improvements in 10-year event-free survival and overall survival were observed for the entire cohort in later studies.

CONCLUSIONS

Patients treated on pediatric trials had better outcomes than those treated on adult trials, but age is a major confounding variable, making it difficult to compare outcomes by cooperative group.

The prognostic significance of IRF8 transcripts in adult patients with acute myeloid leukemia

Interferon regulatory factor 8 (IRF8) is a transcription factor that plays a critical role in normal hematopoiesis, such that disruption of IRF8 activity promotes leukemogenesis. We and others have identified aberrant expression of IRF8 transcripts, including novel splice variants, in acute myeloid leukemia (AML), but studies have not investigated the prognostic significance of these transcripts. Therefore, we developed and optimized quantitative expression assays for both, the wild type, or the reference sequence (WT-IRF8) and novel splice variants (SV-IRF8). These assays were used to quantify IRF8 transcript levels in 194 adult patients with AML, and multivariate analyses investigated the prognostic significance of these expression levels. After adjusting for known prognostic factors, expression levels of WT- or SV-IRF8 transcripts were not significantly associated with complete responses or overall survival. However, increased expression of WT-IRF8 was associated with decreased relapse-free survival (RFS) in both univariate (P = 0.010) and multivariate (P = 0.019) analyses. Similarly, increased expression of SV-IRF8 was associated with a decreased RFS (univariate, P = 0.026 and multivariate, P = 0.021). These studies show for the first time that WT-IRF8 and SV-IRF8 are independent adverse prognostic factors for patients with AML. Additional studies are planned to examine the prognostic significance of IRF8 transcripts in other populations of AML patients.

Induction and postremission strategies in acute myeloid leukemia: state of the art and future directions

Although the past decade has brought improvements in the treatment of AML, particularly for younger individuals, most patients succumb to the disease. With current induction therapy, most patients achieve remission, but the optimal strategy for post-remission therapy is unclear. Refinements to risk classification systems that incorporate additional molecular markers may better guide physicians in recommendations for postremission therapy. The prognosis for older patients with AML remains uniformly poor, because only a minority can benefit from intensive chemotherapy and novel HCT strategies. Despite active investigation, no standard of care has emerged for patients who are not suitable candidates for standard induction therapy. The development of less toxic, more effective therapies for this population is sorely needed. Advances in molecular genetics, immunology, and the biology of normal and malignant hematopoiesis pathogenesis have led to an improved understanding of the pathogenesis of AML and to the discovery of potential therapeutic targets. Until a greater proportion of individuals with AML attain long-term survival, patients should routinely be referred to cancer centers and enrolled in investigational studies.

Prognostic implications of the IDH1 synonymous SNP rs11554137 in pediatric and adult AML: a report from the Children's Oncology Group and SWOG

IDH1 SNP rs11554137 was recently reported in association with poor prognosis in normal karyotype adult acute myeloid leukemia (AML). We aimed to determine the prevalence, clinical associations, and prognostic significance of SNP rs11554137 in unselected pediatric and adult AML patients. Diagnostic marrow specimens from 527 AML patients treated on the pediatric trial Children's Oncology Group-AAML03P1 (N = 253) or adult SWOG trials (N = 274) were analyzed for the presence of the SNP. SNP rs11554137 was present in 11% of all patients. SNP status had no prognostic impact on survival in pediatric patients. In adult AML, overall survival for SNP-positive patients was 10% versus 18% for SNP-negative patients (P = .44). Among the 142 adults who achieved complete remission, 5-year relapse-free survival was significantly worse for SNP-positive patients (0% vs 25%, P = .0014). However, among adults with normal cytogenetics, FLT3/ITD was present in 90% of SNP-positive patients versus 59% of SNP-negative patients (P = .0053). In multivariate analysis, adjusting for the effects of age, cytogenetics, and FLT3/ITD, the independent prognostic effect of SNP positivity was not statistically significant (hazard ratio = 1.72, P = .18). The clinical profile of SNP-positive patients suggests that SNP rs11554137 may have biologic effects that bear further investigation. The clinical trials in this study are registered at http://www.clinicaltrials.gov as #NCT000707174 and #NCT00899171.

Intensively timed combination chemotherapy for the induction of adult patients with acute myeloid leukemia: long-term follow-up of a phase 2 study

BACKGROUND

Despite advances in therapy, the majority of adult patients diagnosed with acute myeloid leukemia (AML) develop disease recurrence and die of their disease. Early intensification of treatment for AML using timed sequential therapy (TST) has been proposed as a means of improving the survival outcome in children. The Children's Cancer Group demonstrated that children with AML who were randomized to receive 2 courses of daunorubicin, cytarabine, thioguanine, etoposide, and dexamethasone (the DCTER regimen) given 10 days apart had an improved event-free survival (EFS) and disease-free survival (DFS) (42% ± 7% and 55% ± 9%, respectively, at 2 years). Reports have suggested an improved outcome in adult patients with AML using TST (at the cost of increased toxicity). The current study was conducted to evaluate the feasibility and effectiveness of the intensively timed DCTER regimen for non-core-binding factor AML in adult patients aged <50 years.

METHODS

Between February 2004 and August 2005, 61 patients received this timed sequential induction regimen. Their outcomes were compared with matched historical patients treated with the combination of idarubicin and cytarabine (IA).

RESULTS

The median follow-up for surviving patients was 67 months (range, 35-85 months). The timed sequential DCTER regimen had a lower complete remission (CR) rate when compared with the IA combination,, (71% vs 80%, respectively), but this appeared to be counterbalanced by a higher long-term leukemia-free survival rate using the intensified regimen (48% vs 30%, respectively) in patients who achieved a CR (P = .06).

CONCLUSIONS

The intensively timed regimen of DCTER was found to induce durable remissions in adult patients with AML, including those patients with high-risk disease. The identification of patients who would potentially benefit from such an intensive regimen may justify the higher early risk of early treatment failure that was found to accompany the intensified DCTER regimen in selected patients.

Prognostic impact of monosomal karyotype in young adult and elderly acute myeloid leukemia: the Southwest Oncology Group (SWOG) experience

Monosomal karyotype (MK), defined as 2 or more monosomies, or a single monosomy in the presence of structural abnormalities, has recently been reported as identifying a distinct subset of acute myeloid leukemia (AML) patients with an extremely poor prognosis. In an effort to confirm this observation, we analyzed the prognostic impact of MK in 1344 AML patients between the ages of 16 and 88 years treated on Southwest Oncology Group protocols. MK was found in 176 (13%) patients. The proportion of patients with MK increased with age, being present in 4% of patients age 30 or younger, but in 20% of those over age 60. Ninety-eight percent of MK cases were within the unfavorable cytogenetic risk category and comprised 40% of this group. The complete remission rate in patients with unfavorable cytogenetics without MK was 34% versus 18% with MK (P < .01). The 4-year overall survival of patients with unfavorable cytogenetics but without MK was 13% in contrast to a 4-year survival of only 3% with MK (P < .01). Thus, MK defines a sizeable subset of patients with unfavorable cytogenetics who have a particularly poor prognosis.

Molecular alterations of the IDH1 gene in AML: a Children's Oncology Group and Southwest Oncology Group study

Recent whole-genome sequencing efforts led to the identification of IDH1^R132 mutations in AML patients. We studied the prevalence and clinical implications of IDH1 genomic alterations in pediatric and adult AML. Diagnostic DNA from 531 AML patients treated on Children’s Oncology Group trial COG-AAML03P1 (N=257), and Southwest Oncology Group trials SWOG-9031, SWOG-9333, and SWOG-9500 (N=274), were tested for IDH1 mutations. Codon R132 mutations were absent in the pediatric cohort, but were found in 12/274 adult patients (4.4%, 95% CI 2.3-7.5%). IDH1^R132 mutations occurred most commonly in patients with normal karyotype, and those with FLT3/ITD and NPMc mutations. Patients with IDH1^R132 mutations trended towards higher median diagnostic WBC counts (59.2 × 10⁹/L vs. 29.1 × 10⁹/L, P=0.19) than those without mutations, but the two groups did not differ significantly in age, bone marrow blast percentage, overall survival, or relapse-free survival. Eleven patients (2.1%) harbored a novel V71I sequence alteration, which was found to be a germline polymorphism. IDH1 mutations were not detected in pediatric AML, and are uncommon in adult AML.

Diagnosis and management of acute myeloid leukemia in adults: recommendations from an international expert panel, on behalf of the European LeukemiaNet

In 2003, an international working group last reported on recommendations for diagnosis, response assessment, and treatment outcomes in acute myeloid leukemia (AML). Since that time, considerable progress has been made in elucidating the molecular pathogenesis of the disease that has resulted in the identification of new diagnostic and prognostic markers. Furthermore, therapies are now being developed that target disease-associated molecular defects. Recent developments prompted an international expert panel to provide updated evidence- and expert opinion–based recommendations for the diagnosis and management of AML, that contain both minimal requirements for general practice as well as standards for clinical trials. A new standardized reporting system for correlation of cytogenetic and molecular genetic data with clinical data is proposed.

Intensive induction chemotherapy with regimen containing intermediate dose cytarabine in the treatment of de novo acute myeloid leukemia

To improve long-term outcome of de novo acute myeloid leukemia (AML) patients by intermediate dose of cytarabine integrated in induction therapy and to explore the impact of cytogenetic abnormalities on the prognosis. Eighty-seven AML patients were treated with HAD regimen containing intermediate dose cytarabine (IDAra-C) as induction therapy, 83 from which with karyotype results were divided into three cytogenetic groups according to SWOG criteria. Complete remission (CR) rate, disease-free survival (DFS), and overall survival (OS) among different groups were evaluated. The CR rate of the 87 cases was 80/87 (92%). Median DFS and OS have not reached (NR). DFS rates at 1 and 3 years were 76.3% and 63.4%, respectively. OS rates at 1 and 3 years were 86.0% and 58.7%, respectively. According to SWOG criteria, CR rate, median DFS, and OS were 100%, NR and NR for the favorable group; 88.9%, NR, and 16 months for the intermediate group; 83.3%, 4.5 months, and 7.5 months for the adverse group. The differences among the three groups were statistically significant excepting for CR rate between adverse and intermediate groups. HAD regimen containing IDAra-C as induction chemotherapy regimen is effective in de novo AML of adult patients and can achieve higher CR rate and longer survival than standard dose of cytarabine (SDAra-C) regimen. Most of the patients were able to endure the therapy. Cytogenetics is still an important prognostic factor despite of the incorporation of IDAra-C in induction chemotherapy. The differences among the three groups were statistically significant. Am. J. Hematol., 2009. (c) 2009 Wiley-Liss, Inc.

Very late antigen-4 function of myeloblasts correlates with improved overall survival for patients with acute myeloid leukemia

Adhesion of acute myeloid leukemia (AML) blasts in the bone marrow microenvironment confers protection from chemotherapy-induced apoptosis. One mechanism for retention of blasts within the bone marrow is adhesion via very late antigen-4 (VLA-4), the alpha(4)beta(1) integrin heterodimer that binds to its main ligands, fibronectin, and vascular cell adhesion molecule-1 (VCAM-1). To examine the relationship of functional expression of VLA-4 to prognosis in AML, we studied marrow samples from 175 adult AML patients who underwent induction chemotherapy with anthracycline and cytarabine on Southwest Oncology Group trials. The studies included flow cytometry and functional in vitro assays for ligand binding and maximal beta(1) activation. VLA-4 expression varied widely, with mean expression 60.6% for alpha(4), and was not significantly associated with response to chemotherapy, relapse-free, or overall survival (OS). However, increased binding of soluble VCAM-1 via VLA-4 was significantly associated with longer OS, corrected for age (P = .033). Estimated 5-year OS was 31% (95% confidence interval, 14%-48%) in 30 patients with soluble VCAM-1 binding greater than or equal to 40%, compared with 10% (confidence interval, 3%-17%) in 72 patients with lower binding. Adhesion and migratory properties of AML blasts thus appear to influence chemosensitivity and therefore may be therapeutic targets.