M. C. Sauerland

Age-Related Risk Profile and Chemotherapy Dose Response in Acute Myeloid Leukemia: A Study by the German Acute Myeloid Leukemia Cooperative Group

PURPOSE The purpose of the study was to assess the contribution of age and disease variables to the outcome of untreated patients with acute myeloid leukemia (AML) receiving varying intensive induction chemotherapy. PATIENTS AND METHODS Patients 16 to 85 years of age with primary AML, known karyotype, and uniform postremission chemotherapy enrolled onto two consecutive trials were eligible and were randomly assigned to induction either with a standard-dose (cytarabine, daunorubicin, and 6-thioguanine) and a high-dose (cytarabine and mitoxantrone) combination, or with two courses of the high-dose combination. Subgroups were defined by karyotype, nucleophosmin and FLT3 mutation, WBC count, serum lactate dehydrogenase, and residual blasts. RESULTS In 1,284 patients, the overall survival at 4 years in those younger and older than 60 years was 37% versus 16% (P < .001) and the ongoing remission duration was 46% versus 22% (P < .001). Similar age-related differences in outcome were found for all defined subgroups. No difference in outcome according to randomly assigned treatment regimen was observed in any age group or prognostic subset. Regarding prognostic subgroups, molecular factors were also considered. CONCLUSION Under harmonized conditions, older and younger patients with AML show modest differences in their risk profiles and equally no dose response to intensified chemotherapy. Their observed fundamental difference in outcome across all subgroups remains unexplained. Further molecular investigation may elucidate the age effect in AML and identify new targets.

An 86-probe-set gene-expression signature predicts survival in cytogenetically normal acute myeloid leukemia.

Patients with cytogenetically normal acute myeloid leukemia (CN-AML) show heterogeneous treatment outcomes. We used gene-expression profiling to develop a gene signature that predicts overall survival (OS) in CN-AML. Based on data from 163 patients treated in the German AMLCG 1999 trial and analyzed on oligonucleotide microarrays, we used supervised principal component analysis to identify 86 probe sets (representing 66 different genes), which correlated with OS, and defined a prognostic score based on this signature. When applied to an independent cohort of 79 CN-AML patients, this continuous score remained a significant predictor for OS (hazard ratio [HR], 1.85; P = .002), event-free survival (HR = 1.73; P = .001), and relapse-free survival (HR = 1.76; P = .025). It kept its prognostic value in multivariate analyses adjusting for age, FLT3 ITD, and NPM1 status. In a validation cohort of 64 CN-AML patients treated on CALGB study 9621, the score also predicted OS (HR = 4.11; P < .001), event-free survival (HR = 2.90; P < .001), and relapse-free survival (HR = 3.14, P < .001) and retained its significance in a multivariate model for OS. In summary, we present a novel gene-expression signature that offers additional prognostic information for patients with CN-AML.

Acute Myeloid Leukemia With Biallelic CEBPA Gene Mutations and Normal Karyotype Represents a Distinct Genetic Entity Associated With a Favorable Clinical Outcome

PURPOSE CEBPA mutations are found as either biallelic (biCEBPA) or monoallelic (moCEBPA). We set out to explore whether the kind of CEBPA mutation is of prognostic relevance in cytogenetically normal (CN) acute myeloid leukemia (AML). PATIENTS AND METHODS Four hundred sixty-seven homogeneously treated patients with CN-AML were subdivided into moCEBPA, biCEBPA, and wild-type (wt) CEBPA patients. The subgroups were analyzed for clinical parameters and for additional mutations in the NPM1, FLT3, and MLL genes. Furthermore, we obtained gene expression profiles using oligonucleotide microarrays. RESULTS Only patients with biCEBPA had an improved median overall survival when compared with patients with wtCEBPA (not reached v 20.4 months, respectively; P = .018), whereas patients with moCEBPA (20.9 months) and wtCEBPA had a similar outcome (P = .506). Multivariable analysis confirmed biCEBPA, but not moCEBPA, mutations as an independent favorable prognostic factor. Interestingly, biCEBPA mutations, compared with wtCEBPA, were never associated with mutated NPM1 (0% v 43%, respectively; P < .001) and rarely associated with FLT3 internal tandem duplication (ITD; 5% v 23%, respectively; P = .059), whereas patients with moCEBPA had a similar frequency of mutated NPM1 and a significantly higher association with FLT3-ITD compared with patients with wtCEBPA (44% v 23%, respectively; P = .037). Furthermore, patients with biCEBPA showed a homogeneous gene expression profile that was characterized by downregulation of HOX genes, whereas patients with moCEBPA showed greater heterogeneity in their gene expression profiles. CONCLUSION Biallelic disruption of the N and C terminus of CEBPA is required for the favorable clinical outcome of CEBPA-mutated patients and represents a distinct molecular subtype of CN-AML with a different frequency of associated gene mutations. These findings are of great significance for risk-adapted therapeutic strategies in AML.

Double Induction Containing Either Two Courses or One Course of High-Dose Cytarabine Plus Mitoxantrone and Postremission Therapy by Either Autologous Stem-Cell Transplantation or by Prolonged Maintenance for Acute Myeloid Leukemia

PURPOSE Intensification by high-dose cytarabine in postremission or induction therapy and prolonged maintenance are established strategies to improve the outcome in patients with acute myeloid leukemia (AML). Whether additional intensification can add to this effect has not yet been determined. PATIENTS AND METHODS A total of 1,770 patients (age 16 to 85 years) with de novo or secondary AML or high-risk myelodysplastic syndrome (MDS) were randomly assigned upfront for induction therapy containing one course with standard dose and one course with high-dose cytarabine, or two courses with high-dose cytarabine, and in the same step received postremission prolonged maintenance or busulfan/cyclophosphamide chemotherapy with autologous stem-cell transplantation. RESULTS The complete remission rate in patients younger than 60 and > or = 60 years of age was 70% and 53%, respectively. The overall survival at 3 years in the two age groups was 42% and 19%, the relapse-free survival was 40% and 19%, and the ongoing remission duration was 48% and 22%, respectively. There were no significant differences in these results between the two randomized induction arms or between the two postremission therapy arms. There was no significant difference in any prognostic subgroup according to secondary AML/MDS, cytogenetics, WBC, lactate dehydrogenase, and early blast clearance. CONCLUSION The regimen of one course with standard-dose cytarabine and one course with high-dose cytarabine for induction, and prolonged maintenance for postremission chemotherapy in patients with AML is not improved by additional escalation in cytotoxic treatment.

ERG Expression Is an Independent Prognostic Factor and Allows Refined Risk Stratification in Cytogenetically Normal Acute Myeloid Leukemia: A Comprehensive Analysis of ERG, MN1, and BAALC Transcript Levels Using Oligonucleotide Microarrays

PURPOSE Recently, several novel molecular prognostic markers were identified in cytogenetically normal acute myeloid leukemia (CN-AML). In addition to the well-known influence of FLT3, NPM1, and CEBPA mutations, high transcript levels of the ERG, BAALC, and MN1 genes have been associated with inferior outcomes, but the relative importance of these risk markers remains to be defined. PATIENTS AND METHODS We analyzed ERG, BAALC, and MN1 expression levels in a cohort of 210 patients with CN-AML who received intensive chemotherapy. Expression levels of ERG, BAALC, and MN1 were determined in bone marrow samples by using oligonucleotide microarrays. RESULTS High transcript levels of ERG, BAALC, and MN1 were predictors for inferior overall survival (OS) and a lower rate of complete remissions (CRs). There were significant positive correlations between the expression levels of all three genes. ERG expression levels predicted OS in elderly patients (ie, age 60 years or older) with CN-AML (P = .006) as well as in younger patients (P = .013). In multivariate analyses, high ERG expression was independently associated with a lower CR rate (P = .013), shorter event-free survival (P = .008), and shorter OS (P = .005). Patients who had low ERG levels and absent FLT3 internal tandem duplication (ITD) had a 5-year OS of 44%, and patients who had high ERG expression and FLT3 ITD had a 5-year OS of only 5%. CONCLUSION We analyzed a comprehensive set of molecular risk factors in a large, homogeneous CN-AML patient cohort. In this study, high ERG expression levels emerged as a strong negative prognostic factor and provided prognostic information in addition to established molecular markers.

High dose ara-C in the treatment of newly diagnosed acute promyelocytic leukemia: long-term results of the German AMLCG.

The objective of this study for newly diagnosed acute promyelocytic Leukemia (APL) was to evaluate the efficacy of an intensified double induction chemotherapy including high dose ara-C (HD) and all-trans retinoic acid (ATRA) followed by consolidation and 3 years maintenance therapy. In contrast to APL studies stratifying therapy according to pretreatment white blood cell (WBC) count < and ⩾10 × 109/l (low/intermediate and high risk according to the Sanz score), our patients received uniform therapy. From 1994 to 2005, 142 patients (age, 16–60 years) were enrolled. In the low/intermediate (n=105) vs high (n=37) WBC group, the rates of complete remission were 95.2 vs 83.8%, of induction death were 4.8 vs 16.2% (P=0.05) and of molecular remission were 87.5 vs 91.3% (P=1). Long-term overall survival was 84.4 vs 73.0% (P=0.12), event free survival was 78.3 vs 67.3% (P=0.11), relapse free survival was 82.1 vs 80.0% (P=0.83) and the cumulative incidence of relapse was 7.4 vs 11.4% (P=0.46). No relapse or death occurred after 4.7 years. ATRA and intensified chemotherapy including HD ara-C followed by prolonged maintenance therapy reduced the relapse risk in high risk patients. Pretreatment WBC count ⩾10 × 109/l count was no relevant prognostic factor for relapse.

Early assessment of minimal residual disease in AML by flow cytometry during aplasia identifies patients at increased risk of relapse

In acute myeloid leukemia (AML), assessment of minimal residual disease (MRD) by flow cytometry (flow MRD) after induction and consolidation therapy has been shown to provide independent prognostic information. However, data on the value of earlier flow MRD assessment are lacking. Therefore, the value of flow MRD detection was determined during aplasia in 178 patients achieving complete remission after treatment according to AMLCG (AML Cooperative Group) induction protocols. Flow MRD positivity during aplasia predicted poor outcome (5-year relapse-free survival (RFS) 16% vs 43%, P<0.001) independently from age and cytogenetic risk group (hazard ratio for MRD positivity 1.71; P=0.009). Importantly, the prognosis of patients without detectable MRD was neither impacted by morphological blast count during aplasia nor by MRD status postinduction. Early flow MRD was also evaluated in the context of existing risk factors. Flow MRD was prognostic within the intermediate cytogenetic risk group (5-year RFS 15% vs 37%, P=0.016) as well as for patients with normal karyotype and NPM1 mutations (5-year RFS 13% vs 49%, P=0.02) or FLT3-ITD (3-year RFS rates 9% vs 44%, P=0.016). Early flow MRD assessment can improve current risk stratification approaches by prediction of RFS in AML and might facilitate adaptation of postremission therapy for patients at high risk of relapse.

Molecular response assessment by quantitative real-time polymerase chain reaction after induction therapy in NPM1-mutated patients identifies those at high risk of relapse

Monitoring minimal residual disease is an important way to identify patients with acute myeloid leukemia at high risk of relapse. In this study we investigated the prognostic potential of minimal residual disease monitoring by quantitative real-time polymerase chain reaction analysis of NPM1 mutations in patients treated in the AMLCG 1999, 2004 and 2008 trials. Minimal residual disease was monitored - in aplasia, after induction therapy, after consolidation therapy, and during follow-up - in 588 samples from 158 patients positive for NPM1 mutations A, B and D (with a sensitivity of 10−6). One hundred and twenty-seven patients (80.4%) achieved complete remission after induction therapy and, of these, 56 patients (44.1%) relapsed. At each checkpoint, minimal residual disease cut-offs were calculated. After induction therapy a cut-off NPM1 mutation ratio of 0.01 was associated with a high hazard ratio of 4.26 and the highest sensitivity of 76% for the prediction of relapse. This was reflected in a cumulative incidence of relapse after 2 years of 77.8% for patients with ratios above the cut-off versus 26.4% for those with ratios below the cut-off. In the favorable subgroup according to European LeukemiaNet, the cut-off after induction therapy also separated the cohort into two prognostic groups with a cumulative incidence of relapse of 76% versus 6% after 2 years. Our data demonstrate that in addition to pre-therapeutic factors, the course of minimal residual disease in an individual is an important prognostic factor and could be included in clinical trials for the guidance of post-remission therapy. The trials from which data were obtained were registered at www.clinicaltrials.gov (#NCT01382147, #NCT00266136) and at the European Leukemia Trial Registry (#LN_AMLINT2004_230).

Clinical aspects of acute myeloid leukemias of the FAB types M3 and M4Eo

Acute promyelocytic leukemia (AML FAB M3, APL) and acute myelomonocytic leukemia with abnormal eosinophils (AML M4Eo) are considered distinct entities with characteristic clinical, morphological, cytogenetic, and prognostic features. Promyelocytic leukemia is characterized by abnormal promyelocytes replacing normal hematopoiesis associated with a translocation between the long arms of chromosomes 15 and 17 t (15; 17), severe coagulopathy, and responsiveness to all-trans retinoic acid (tretinoin). Characteristic features of AML M4Eo are a myelomonocytic marrow infiltration, eosinophils with abnormal immature granules positive for chloroacetate esterase, an inversion or translocation of chromosome 16, and an increased risk of meningeal relapses. Prognosis of both types of AML has been reported to be better than prognosis of the other entities combined. Since most of the published data were collected from heterogeneous patient populations treated with various chemotherapeutic regimens, we have analyzed treatment outcome of AML M3 and M4Eo in the AMLCG-85 study for patients younger than 60 years. For the total population of 594 patients of this study, CR rate was 68.89%, early death rate 11.60%, and no or partial remission was achieved in 19.51% of the cases. Of 40 patients with AML M3 or M3v complete remission was attained in 62.5%. Nine patients died within 42 days after the start of antileukemic therapy (22.5%). Of these nine, four died because of infection, five because of bleeding. Relapse-free survival rate was 59% after 3 years, significantly better than the respective curve of the other FAB types combined (35% after 3 years). In AML M4Eo, 91.7% of the 24 patients reached complete remission. The early death rate was 8.3%. No case of nonresponse was seen. Relapse-free survival rate was 49% after 3 years compared with 35% for the other types combined.

Monoallelic CEBPA mutations in normal karyotype acute myeloid leukemia: independent favorable prognostic factor within NPM1 mutated patients

We and others have shown that cytogenetically normal (CN)-AML patients with biallelic CEBPA gene mutations (biCEBPA) represent a molecularly distinct group with a favorable prognosis. Patients carrying a monoallelic CEBPA mutation (moCEBPA), however, show no different outcome compared to patients with wildtype CEBPA, and these mutations are frequently associated with mutated NPM1 or FLT3-ITD. So far, no molecular or clinical hallmark has been identified to prognostically distinguish moCEBPA patients from patients with wildtype CEBPA. Therefore, we used the data of 663 CN-AML patients treated within the AMLCG 1999 trial to explore the prognostic value of moCEBPA in the context of concomitant clinical and molecular markers (mutated NPM1, FLT3-ITD). Multiple Cox regression in 515 patients adjusting for all available potential confounders revealed that the NPM1 mutation modified the prognostic value of moCEBPA with respect to overall survival (OS, p = 0.017) and event-free survival (EFS, p = 0.011). MoCEBPA was beneficial in NPM1 mutated patients: adjusted OS–hazard ratio (HR) 0.09, 95% confidence interval (CI) 0.01–0.63, p = 0.016; EFS–HR (95% CI) 0.16 (0.04–0.65), p = 0.010. In contrast, moCEBPA had no prognostic impact in patients with wildtype NPM1: OS–HR (95% CI) 1.08 (0.59–1.97), p = 0.804; EFS–HR (95% CI) 1.12 (0.64–1.96), p = 0.682. We found no prognostic effect modification for moCEBPA by FLT3-ITD. The presence of a moCEBPA mutation was shown to be associated with prolonged survival in NPM1 mutated CN-AML patients. Confirmation of these results in larger studies will clarify whether an additional moCEBPA mutation influences the risk stratification of patients with an NPM1 mutated/FLT3-ITD positive genotype.