Antifungal Prophylaxis in AML Patients Receiving Intensive Induction Chemotherapy: A Prospective Observational Study From the Acute Leukaemia French Association (ALFA) Group.

BACKGROUND: Although recommended in patients with acute myeloblastic leukaemia (AML) after induction chemotherapy, real-life use of antifungal prophylaxis (AFP) is different among centres. MATERIALS AND METHODS: This is an ancillary study to a randomized trial on intensive induction chemotherapy in AML patients (ALFA-0702/NCT00932412), where AFP with posaconazole was recommended. IFIs were graded by investigators and by central reviewers according to the revised EORTC definitions. Experts conclusions were compared to the investigators' ones. RESULTS: A total of 677 patients were included. Four AFP strategies were reported: Group-1: no AFP (n = 203, 30%), Group-2: posaconazole (n = 241, 36%), Group-3: posaconazole with other AFP (n = 142, 21%), Group-4: other AFP (n = 91, 13%). Experts graded more IFI than investigators: proven/probable IFI, 9.0% (n = 61) versus 6.2% (n = 42). The cumulative incidence at day60 of probable/proven IFI was 13.9% (Group-1); 7.9% (Group-2); 5.6% (Group-3); and 6.6% (Group-4). IFI onset was 26 (19-31) days after induction in Groups 2-3, versus 16 (9-25) days in Group 1 and 20 (12-24) days in Group 4 (P< .001). After a median follow-up of 27.5 months (0.4-73.4), the mortality rate was 38.3%, with 5.4% attributed to IFI. In multivariate analysis, IFI occurrence was an independent risk of death (HR5.63, 95%-CI 2.62-12.08, P< .001). EORTC recommendations were applied in only 57% of patients. In patients without IFI, the rate of AML complete remission was higher. CONCLUSIONS: In AML patients, AFP delayed the onset of IFI in addition of decreasing their rate. The frequent misidentification of IFI impacts their appropriate management according to recommendations. hematological remission was more frequent in patients without IFI.

Early detection of WT1 measurable residual disease identifies high-risk patients, independent of transplantation in AML.

WT1 overexpression is frequently identified in acute myeloid leukemia (AML) and has been reported to be a potential marker for monitoring measurable residual disease (MRD). We evaluated the use of postinduction WT1 MRD level as a prognostic factor, as well as the interaction between postinduction WT1 MRD response and the effect of allogeneic stem cell transplantation (allo-SCT) in the first complete remission (CR). In the ALFA-0702 trial, patients with AML, aged 18 to 59, had a prospective quantification of WT1 MRD. The occurrence of a WT1 MRD ratio >2.5% in bone marrow or >0.5% in peripheral blood was defined as MRDhigh, and ratios below these thresholds were defined as MRDlow. The prognostic value of MRD after induction chemotherapy was assessed in 314 patients in first CR by comparing the risk of relapse, the relapse-free survival (RFS), and the overall survival (OS). Interaction between MRD response and the allo-SCT effect was evaluated in patients by comparing the influence of allo-SCT on the outcomes of patients with MRDhigh with those with MRDlow. The results showed that patients with MRDhigh after induction had a higher risk of relapse and a shorter RFS and OS. The MRD response remained of strong prognostic value in the subset of 225 patients with intermediate-/unfavorable-risk AML who were eligible for allo-SCT, because patients with MRDhigh had a significantly higher risk of relapse resulting in worse RFS and OS. The effect of allo-SCT was higher in patients with MRDlow than in those with MRDhigh, but not significantly different. The early WT1 MRD response highlights a population of high-risk patients in need of additional therapy.

Outcomes following hematopoietic stem cell transplantation in patients treated with standard chemotherapy with or without gemtuzumab ozogamicin for acute myeloid leukemia.

The phase 3 ALFA-0701 trial demonstrated improved outcomes with fractionated-dose gemtuzumab ozogamicin (GO) combined with standard chemotherapy vs. standard chemotherapy alone in adults with de novo acute myeloid leukemia (AML). We examined post-transplant outcomes and occurrence of hepatic veno-occlusive disease/sinusoidal obstruction syndrome (VOD/SOS) in patients who received hematopoietic stem cell transplantation (HSCT) as follow-up therapy in ALFA-0701. Patients aged 50-70 years were randomized to standard chemotherapy with or without GO (3 mg/m2 on days 1, 4, and 7 of induction and day 1 on each of two consolidation courses). Allogeneic HSCT was recommended for patients in first complete remission with matched (related or unrelated) donor, except those with core-binding factor AML or normal karyotype and either NPM1+/FLT3-ITDwt or CEBPA+ AML. Eighty-five patients (GO: n = 32; control: n = 53) received HSCT in first complete remission or after relapse/primary induction failure. Three patients (GO: n = 2; control: n = 1 [received GO as follow-up therapy]) developed VOD/SOS after HSCT or conditioning. Post-transplant survival, non-relapse mortality, and relapse were not different between arms. Results indicate fractionated-dose GO as part of induction and consolidation chemotherapy for AML does not induce excess post-transplant VOD/SOS or mortality and thus does not preclude the use of HSCT as consolidation treatment.

A transcriptomic continuum of differentiation arrest identifies myeloid interface acute leukemias with poor prognosis.

Classification of acute lymphoblastic and myeloid leukemias (ALL and AML) remains heavily based on phenotypic resemblance to normal hematopoietic precursors. This framework can provide diagnostic challenges for immunophenotypically heterogeneous immature leukemias, and ignores recent advances in understanding of developmental multipotency of diverse normal hematopoietic progenitor populations that are identified by transcriptional signatures. We performed transcriptional analyses of a large series of acute myeloid and lymphoid leukemias and detected significant overlap in gene expression between cases in different diagnostic categories. Bioinformatic classification of leukemias along a continuum of hematopoietic differentiation identified leukemias at the myeloid/T-lymphoid interface, which shared gene expression programs with a series of multi or oligopotent hematopoietic progenitor populations, including the most immature CD34+CD1a-CD7- subset of early thymic precursors. Within these interface acute leukemias (IALs), transcriptional resemblance to early lymphoid progenitor populations and biphenotypic leukemias was more evident in cases originally diagnosed as AML, rather than T-ALL. Further prognostic analyses revealed that expression of IAL transcriptional programs significantly correlated with poor outcome in independent AML patient cohorts. Our results suggest that traditional binary approaches to acute leukemia categorization are reductive, and that identification of IALs could allow better treatment allocation and evaluation of therapeutic options.

Biomarkers of Gemtuzumab Ozogamicin Response for Acute Myeloid Leukemia Treatment.

Gemtuzumab ozogamicin (GO, Mylotarg®) consists of a humanized CD33-targeted antibody-drug conjugated to a calicheamicin derivative. Growing evidence of GO efficacy in acute myeloid leukemia (AML), demonstrated by improved outcomes in CD33-positive AML patients across phase I to III clinical trials, led to the Food and Drug Administration (FDA) approval on 1 September 2017 in CD33-positive AML patients aged 2 years and older. Discrepancies in GO recipients outcome have raised significant efforts to characterize biomarkers predictive of GO response and have refined the subset of patients that may strongly benefit from GO. Among them, CD33 expression levels, favorable cytogenetics (t(8;21), inv(16)/t(16;16), t(15;17)) and molecular alterations, such as NPM1, FLT3-internal tandem duplications and other signaling mutations, represent well-known candidates. Additionally, in depth analyses including minimal residual disease monitoring, stemness expression (LSC17 score), mutations or single nucleotide polymorphisms in GO pathway genes (CD33, ABCB1) and molecular-derived scores, such as the recently set up CD33_PGx6_Score, represent promising markers to enhance GO response prediction and improve patient management.

Vitamin D Receptor Controls Cell Stemness in Acute Myeloid Leukemia and in Normal Bone Marrow.

Vitamin D (VD) is a known differentiating agent, but the role of VD receptor (VDR) is still incompletely described in acute myeloid leukemia (AML), whose treatment is based mostly on antimitotic chemotherapy. Here, we present an unexpected role of VDR in normal hematopoiesis and in leukemogenesis. Limited VDR expression is associated with impaired myeloid progenitor differentiation and is a new prognostic factor in AML. In mice, the lack of Vdr results in increased numbers of hematopoietic and leukemia stem cells and quiescent hematopoietic stem cells. In addition, malignant transformation of Vdr-/- cells results in myeloid differentiation block and increases self-renewal. Vdr promoter is methylated in AML as in CD34+ cells, and demethylating agents induce VDR expression. Association of VDR agonists with hypomethylating agents promotes leukemia stem cell exhaustion and decreases tumor burden in AML mouse models. Thus, Vdr functions as a regulator of stem cell homeostasis and leukemic propagation.

Mutational profile and benefit of gemtuzumab ozogamicin in acute myeloid leukemia.

Acute myeloid leukemia (AML) is a highly heterogeneous disease both in terms of genetic background and response to chemotherapy. Although molecular aberrations are routinely used to stratify AML patients into prognostic subgroups when receiving standard chemotherapy, the predictive value of the genetic background and co-occurring mutations remains to be assessed when using newly approved antileukemic drugs. In the present study, we retrospectively addressed the question of the predictive value of molecular events on the benefit of the addition of gemtuzumab ozogamicin (GO) to standard front-line chemotherapy. Using the more recent European LeukemiaNet (ELN) 2017 risk classification, we confirmed that the benefit of GO was restricted to the favorable (hazard ratio [HR], 0.54, 95% confidence interval [CI], 0.30-0.98) and intermediate (HR, 0.57; 95% CI, 0.33-1.00) risk categories, whereas it did not influence the outcome of patients within the adverse risk subgroup (HR, 0.93; 95% CI, 0.61-1.43). Interestingly, the benefit of GO was significant for patients with activating signaling mutations (HR, 0.43; 95% CI, 0.28-0.65), which correlated with higher CD33 expression levels. These results suggest that molecular aberrations could be critical for future differentially tailored treatments based on integrated genetic profiles that are able to predict the benefit of GO on outcome.

Gemtuzumab ozogamicin for de novo acute myeloid leukemia: final efficacy and safety updates from the open-label, phase III ALFA-0701 trial.

The randomized, phase III ALFA-0701 trial showed that a reduced and fractionated dose of gemtuzumab ozogamicin added to standard front-line chemotherapy significantly improves event-free survival (EFS) in adults with de novo acute myeloid leukemia (AML). Here we report an independent review of EFS, final overall survival (OS), and additional safety results from ALFA-0701. Patients (n=271) aged 50-70 years with de novo AML were randomized to receive conventional front-line induction chemotherapy (3+7daunorubicin+cytarabine) with/without gemtuzumab ozogamicin 3 mg/m2 on days 1, 4, and 7 during induction. Patients in remission following induction therapy received 2 courses of consolidation therapy (daunorubicin+cytarabine) with/without gemtuzumab ozogamicin (3 mg/m2/day on day 1) according to their initial randomization. The primary end point was investigator-assessed EFS. Secondary end points included OS and safety. A blinded independent review confirmed the investigator-assessed EFS results [August 1, 2011; hazard ratio (HR) 0.66; 95% Confidence Interval (CI): 0.49-0.89; 2-sided P=0.006], corresponding to a 34% reduction in risk of events in the gemtuzumab ozogamicin versus control arm. Final OS at April 30, 2013 favored gemtuzumab ozogamicin but was not significant. No differences in early death rate were observed between arms. The main toxicity associated with gemtuzumab ozogamicin was prolonged thrombocytopenia. Veno-occlusive disease (including after transplant) was observed in 6 patients in the gemtuzumab ozogamicin arm and 2 in the control arm. In conclusion, gemtuzumab ozogamicin added to standard intensive chemotherapy has a favorable benefit/risk ratio. These results expand front-line treatment options for adult patients with previously untreated AML. (Trial registered at clinicaltrials.gov; identifier: 00927498).

Clinical relevance of IDH1/2 mutant allele burden during follow-up in acute myeloid leukemia. A study by the French ALFA group.

Assessment of minimal residual disease has emerged as a powerful prognostic factor in acute myeloid leukemia. In this study, we investigated the potential of IDH1/2 mutations as targets for minimal residual disease assessment in acute myeloid leukemia, since these mutations collectively occur in 15-20% of cases of acute myeloid leukemia and now represent druggable targets. We employed droplet digital polymerase chain reaction assays to quantify IDH1R132, IDH2R140, and IDH2R172 mutations on genomic DNA in 322 samples from 103 adult patients with primary IDH1/2 mutant acute myeloid leukemia and enrolled on Acute Leukemia French Association (ALFA) - 0701 or -0702 clinical trials. The median IDH1/2 mutant allele fraction in bone marrow samples was 42.3% (range, 8.2 - 49.9%) at diagnosis of acute myeloid leukemia, and below the detection limit of 0.2% (range, <0.2 - 39.3%) in complete remission after induction therapy. In univariate analysis, the presence of a normal karyotype, a NPM1 mutation, and an IDH1/2 mutant allele fraction <0.2% in bone marrow after induction therapy were statistically significant predictors of longer disease-free survival. In multivariate analysis, these three variables remained significantly predictive of disease-free survival. In 7/103 (7%) patients, IDH1/2 mutations persisted at high levels in complete remission, consistent with the presence of an IDH1/2 mutation in pre-leukemic hematopoietic stem cells. Five out of these seven patients subsequently relapsed or progressed toward myelodysplastic syndrome, suggesting that patients carrying the IDH1/2 mutation in a pre-leukemic clone may be at high risk of hematologic evolution.

Randomized Phase II Study of Clofarabine-Based Consolidation for Younger Adults With Acute Myeloid Leukemia in First Remission.

Purpose To evaluate the efficacy and safety of a clofarabine-based combination (CLARA) versus conventional high-dose cytarabine (HDAC) as postremission chemotherapy in younger patients with acute myeloid leukemia (AML). Patients and Methods Patients age 18 to 59 years old with intermediate- or unfavorable-risk AML in first remission and no identified donor for allogeneic stem-cell transplantation (SCT) were eligible. Two hundred twenty-one patients were randomly assigned to receive three CLARA or three HDAC consolidation cycles. The primary end point was relapse-free survival (RFS). To handle the confounding effect of SCT that could occur in patients with late donor identification, hazard ratios (HRs) of events were adjusted on the time-dependent treatment × SCT interaction term. Results At 2 years, RFS was 58.5% (95% CI, 49% to 67%) in the CLARA arm and 46.5% (95% CI, 37% to 55%) in the HDAC arm. Overall, 110 patients (55 in each arm) received SCT in first remission. On the basis of a multivariable Cox-adjusted treatment × SCT interaction, the HR of CLARA over HDAC before or in absence of SCT was 0.65 (95% CI, 0.43 to 0.98; P = .041). In a sensitivity analysis, when patients who received SCT in first remission were censored at SCT time, 2-year RFS was 53.3% (95% CI, 39% to 66%) in the CLARA arm and 31.0% (95% CI, 19% to 43%) in the HDAC arm (HR, 0.63; 95% CI, 0.41 to 0.98; P = .043). Gain in RFS could be related to the lower cumulative incidence of relapse observed in the CLARA arm versus the HDAC arm (33.9% v 46.4% at 2 years, respectively; cause-specific HR, 0.61; 95% CI, 0.40 to 0.94; P = .025). CLARA cycles were associated with higher hematologic and nonhematologic toxicity than HDAC cycles. Conclusion These results suggest that CLARA might be considered as a new chemotherapy option in younger patients with AML in first remission.

The Plasmair Decontamination System Is Protective Against Invasive Aspergillosis in Neutropenic Patients.

OBJECTIVE Invasive aspergillosis (IA) is a rare but severe infection caused by Aspergillus spp. that often develops in immunocompromised patients. Lethality remains high in this population. Therefore, preventive strategies are of key importance. The impact of a mobile air decontamination system (Plasmair, AirInSpace, Montigny-le-Bretonneux, France) on the incidence of IA in neutropenic patients was evaluated in this study. DESIGN Retrospective cohort study METHODS Patients with chemotherapy-induced neutropenia lasting 7 days or more were included over a 2-year period. Cases of IA were confirmed using the revised European Organization for Research and Treatment of Cancer (EORTC) criteria. We took advantage of a partial installation of Plasmair systems in the hematology intensive care unit during this period to compare patients treated in Plasmair-equipped versus non-equipped rooms. Patients were assigned to Plasmair-equipped or non-equipped rooms depending only on bed availability. Differences in IA incidence in both groups were compared using Fisher's exact test, and a multivariate analysis was performed to take into account potential confounding factors. RESULTS Data from 156 evaluable patients were available. Both groups were homogenous in terms of age, gender, hematological diagnosis, duration of neutropenia, and prophylaxis. A total of 11 cases of probable IA were diagnosed: 10 in patients in non-equipped rooms and only 1 patient in a Plasmair-equipped room. The odds of developing IA were much lower for patients hospitalized in Plasmair-equipped rooms than for patients in non-equipped rooms (P=.02; odds ratio [OR] =0.11; 95% confidence interval [CI], 0.00-0.84). CONCLUSION In this study, Plasmair demonstrated a major impact in reducing the incidence of IA in neutropenic patients with hematologic malignancies. Infect Control Hosp Epidemiol 2016;37:845-851.

Quantification of EVI1 transcript levels in acute myeloid leukemia by RT-qPCR analysis: A study by the ALFA Group.

EVI1 overexpression confers poor prognosis in acute myeloid leukemia (AML). Quantification of EVI1 expression has been mainly assessed by real-time quantitative PCR (RT-qPCR) based on relative quantification of EVI1-1D splice variant. In this study, we developed a RT-qPCR assay to perform quantification of EVI1 expression covering the different splice variants. A sequence localized in EVI1 exons 14 and 15 was cloned into plasmids that were used to establish RT-qPCR standard curves. Threshold values to define EVI1 overexpression were determined using 17 bone marrow (BM) and 31 peripheral blood (PB) control samples and were set at 1% in BM and 0.5% in PB. Samples from 64 AML patients overexpressing EVI1 included in the ALFA-0701 or -0702 trials were collected at diagnosis and during follow-up (n=152). Median EVI1 expression at AML diagnosis was 23.3% in BM and 3.6% in PB. EVI1 expression levels significantly decreased between diagnostic and post-induction samples, with an average variation from 21.6% to 3.56% in BM and from 4.0% to 0.22% in PB, but did not exceed 1 log10 reduction. Our study demonstrates that the magnitude of reduction in EVI1 expression levels between AML diagnosis and follow-up is not sufficient to allow sensitive detection of minimal residual disease.

IDH1/2 but not DNMT3A mutations are suitable targets for minimal residual disease monitoring in acute myeloid leukemia patients: a study by the Acute Leukemia French Association.

Acute myeloid leukemia (AML) is a heterogeneous disease. Even within the same NPM1-mutated genetic subgroup, some patients harbor additional mutations in FLT3, IDH1/2, DNMT3A or TET2. Recent studies have shown the prognostic significance of minimal residual disease (MRD) in AML but it remains to be determined which molecular markers are the most suitable for MRD monitoring. Recent advances in next-generation sequencing (NGS) have provided the opportunity to use multiple molecular markers. In this study, we used NGS technology to assess MRD in 31 AML patients enrolled in the ALFA-0701 trial and harboring NPM1 mutations associated to IDH1/2 or DNMT3A mutations. NPM1 mutation-based MRD monitoring was performed by RTqPCR. IDH1/2 and DNMT3A mutations were quantified by NGS using an Ion Torrent Proton instrument with high coverage (2 million reads per sample). The monitoringof IDH1/2 mutations showed that these mutations were reliable MRD markers that allowed the prediction of relapse in the majority of patients. Moreover, IDH1/2 mutation status predicted relapse or disease evolution in 100% of cases if we included the patient who developed myelodysplastic syndrome. In contrast, DNMT3A mutations were not correlated to the disease status, as we found that a preleukemic clone with DNMT3A mutation persisted in 40% of the patients who were in complete remission, reflecting the persistence of clonal hematopoiesis.

Erosion of the chronic myeloid leukaemia stem cell pool by PPARγ agonists.

Whether cancer is maintained by a small number of stem cells or is composed of proliferating cells with approximate phenotypic equivalency is a central question in cancer biology. In the stem cell hypothesis, relapse after treatment may occur by failure to eradicate cancer stem cells. Chronic myeloid leukaemia (CML) is quintessential to this hypothesis. CML is a myeloproliferative disorder that results from dysregulated tyrosine kinase activity of the fusion oncoprotein BCR-ABL. During the chronic phase, this sole genetic abnormality (chromosomal translocation Ph(+): t(9;22)(q34;q11)) at the stem cell level causes increased proliferation of myeloid cells without loss of their capacity to differentiate. Without treatment, most patients progress to the blast phase when additional oncogenic mutations result in a fatal acute leukaemia made of proliferating immature cells. Imatinib mesylate and other tyrosine kinase inhibitors (TKIs) that target the kinase activity of BCR-ABL have improved patient survival markedly. However, fewer than 10% of patients reach the stage of complete molecular response (CMR), defined as the point when BCR-ABL transcripts become undetectable in blood cells. Failure to reach CMR results from the inability of TKIs to eradicate quiescent CML leukaemia stem cells (LSCs). Here we show that the residual CML LSC pool can be gradually purged by the glitazones, antidiabetic drugs that are agonists of peroxisome proliferator-activated receptor-γ (PPARγ). We found that activation of PPARγ by the glitazones decreases expression of STAT5 and its downstream targets HIF2α and CITED2, which are key guardians of the quiescence and stemness of CML LSCs. When pioglitazone was given temporarily to three CML patients in chronic residual disease in spite of continuous treatment with imatinib, all of them achieved sustained CMR, up to 4.7 years after withdrawal of pioglitazone. This suggests that clinically relevant cancer eradication may become a generally attainable goal by combination therapy that erodes the cancer stem cell pool.

Defective NK Cells in Acute Myeloid Leukemia Patients at Diagnosis Are Associated with Blast Transcriptional Signatures of Immune Evasion.

Acute myeloid leukemia (AML) is a heterogeneous group of malignancies that may be sensitive to the NK cell antitumor response. However, NK cells are frequently defective in AML. In this study, we found in an exploratory cohort (n = 46) that NK cell status at diagnosis of AML separated patients in two groups with a different clinical outcome. Patients with a deficient NK cell profile, including reduced expression of some activating NK receptors (e.g., DNAX accessory molecule-1, NKp46, and NKG2D) and decreased IFN-γ production, had a significantly higher risk of relapse (p = 0.03) independently of cytogenetic classification in multivariate analysis. Patients with defective NK cells showed a profound gene expression decrease in AML blasts for cytokine and chemokine signaling (e.g., IL15, IFNGR1, IFNGR2, and CXCR4), Ag processing (e.g., HLA-DRA, HLA-DRB1, and CD74) and adhesion molecule pathways (e.g., PVR and ICAM1). A set of 388 leukemic classifier genes defined in the exploratory cohort was independently validated in a multicentric cohort of 194 AML patients. In total, these data evidenced the interplay between NK cells and AML blasts at diagnosis allowing an immune-based stratification of AML patients independently of clinical classifications.

Next-generation sequencing of FLT3 internal tandem duplications for minimal residual disease monitoring in acute myeloid leukemia.

Minimal Residual Disease (MRD) detection can be used for early intervention in relapse, risk stratification, and treatment guidance. FLT3 ITD is the most common mutation found in AML patients with normal karyotype. We evaluated the feasibility of NGS with high coverage (up to 2.4.10(6) PE fragments) for MRD monitoring on FLT3 ITD. We sequenced 37 adult patients at diagnosis and various times of their disease (64 samples) and compared the results with FLT3 ITD ratios measured by fragment analysis. We found that NGS could detect variable insertion sites and lengths in a single test for several patients. We also showed mutational shifts between diagnosis and relapse, with the outgrowth of a clone at relapse different from that dominant at diagnosis. Since NGS is scalable, we were able to adapt sensitivity by increasing the number of reads obtained for follow-up samples, compared to diagnosis samples. This technique could be applied to detect biological relapse before its clinical consequences and to better tailor treatments through the use of FLT3 inhibitors. Larger cohorts should be assessed in order to validate this approach.