Search

We studied pre-transplant minimal residual disease (MRD) in 224 patients (median age 44 years; range 17-65) with acute myeloid leukemia (AML) undergoing allogeneic stem cell transplant (HSCT) in complete remission. MRD was evaluated on marrow samples using multicolor flow cytometry (MFC) and assessment of WT1 gene expression. Both methods showed a strong prognostic value and their combination allowed the identification of 3 groups of patients with different risk of relapse. In multivariate analysis, combined MRD was the only predictor of cumulative incidence of relapse, regardless of donor type, conditioning regimen, first or second CR at HSCT, HSCT year and ELN risk group. Multivariate regression model showed that only negative combined MRD status (p

Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a poor prognosis myeloid malignancy characterized by an atypical phenotype (CD123+, CD56+, and CD4+). We reported that BPDCN-like phenotype (CD123+ and either CD56+ or CD4+ or both) confers poor prognosis to acute myeloblastic leukemia (AML) patients with mutated NPM1. Here, we evaluated the incidence and the prognostic relevance of BPDCN-like phenotype in cytogenetically normal AML (CN-AML) patients. From 2006 to 2016, 83 young (age60 yrs), consecutive, CN-AML patients underwent intensive treatment. Fifteen patients (18%) showed a BPDCN-like phenotype with no difference between

NPM1 and FLT3 mutational status assessment is recommended in acute myeloid leukemia (AML) at diagnosis by European Leukemia Net (ELN) risk stratification. The presence of NPM1 mutation (NPM1-mut) partially overcomes the negative prognostic impact of FLT3-ITD, which is also modulated by FLT3-ITD/wild-type allelic ratio. Targeted drugs are available for FLT3-mutated AML but no data are available so far on the efficacy of intensified front-line regimens in overcoming the negative prognostic role of FLT3-ITD mutation. We investigated the efficacy of an intensive fludarabine, high dose cytarabine (ARA-C) and Idarubicin (IDA) induction regimen (FLAI) as frontline treatment for fit, de novo AML patients according to NPM1 and FLT3-ITD mutational status. One-hundred and forty-nine consecutive AML patients, treated in 3 Hematology Italian centers from January 2008 to January 2018, were included in this analysis. Twenty nine patients had isolated FLT3-ITD, 59 concomitant FLT3-ITD and NPM1-mut and 61 isolated NPM1-mut. Median age was 51 yrs (range: 18-65). All patients received FLAI induction (fludarabine 30 mg/sqm and ARA-C 2g/sqm on days 1 to 5 plus IDA 10 mg/sqm on days 1-3-5). For patients achieving CR fludarabine was omitted on II induction and IDA dose was increased to 12 mg/sqm. Before ELN 2017 risk stratification was adopted, patients with isolated FLT3-ITD mutation were scheduled to receive allogeneic bone marrow transplantation (allo-BMT) in first CR regardless of allelic burden. For patients with AML with NPM1 mutation and concomitant FLT3-ITD indication to allo-BMT in 1st complete remission was mainly based on minimal residual disease (MRD) status. MRD was evaluated on marrow samples using multicolor flow-cytometry (MFC) or NPM1 expression levels. Negative MFC-MRD was defined by the presence of less than 25 clustered leukemic cells/105 total events (threshold of 0.025%, Minetto et. al, BJH 2019). NPM1-mut (NPM1-A, B and D) was measured using Muta Quant Kit Ipsogen from Qiagen. FLT3-ITD allelic burden was available in31/64 of FLT3-ITD patients. Overall, 60-days mortality was 4.7%. After first induction cycles, 129 patients achieved CR (86.6%). Thirty-five/129 (25.5%) CR patients underwent BMT in first CR. After a median follow up of 68 months, 3-year overall survival (OS) was 58.6% (median not reached). In univariate analysis OS duration was affected by NPM1, FLT3 mutational status and ELN risk score. However, NPM1-mutated patient was not negatively affected by the presence of FLT3-ITD, regardless of allelic burden. This observation was even more evident in patients younger than 55 yrs (3 yy OS 64% and 68% for NPM1-mutated with or w/o FLT3-ITD, respectively (p=n.s, Figure 1), regardless of FLT3-ITD allelic burden. ELN 2017 high risk patients displayed the worst prognosis (3-year OS 35.2%). Multivariate analysis showed that NPM1 mutation was the strongest predictor of survival. In order to assess the impact of allo-BMT in 1st CR we performed a Landmark Analysis including patients alive and in CR at day 90. Interestingly, performing allo-BMT in 1st CR did not impact OS in the whole cohort of patients and irrespectively of NPM1 and FLT3 mutational status. The only subgroup who benefit from allo-BMT in first CR was high risk ELN2017 (p Despite the potential bias due to the retrospective nature of the analysis, our data indicate that intensive fludarabine-high dose cytarabine-based induction exerts a strong anti-leukemic efficacy in younger AML patients carrying NPM1 mutation irrespectively of FLT3 mutational status. Our data potentially question the role of BMT in first CR in this setting. Figure Disclosures Bocchia: CELGENE: Honoraria; Incyte: Honoraria.

Background: Minimal residual disease (MRD) assessment retains high prognostic value in Acute Myeloid Leukemia patients (AML) undergoing intensive induction therapy. Widely available MRD techniques include multicolour flow cytometry (MFC), RT-PCR for recurrent genetic lesion and, for patients lacking specific markers, RT-PCR for the pan- leukemic marker WT1. However, most of the data on the prognostic value of MRD come from trials including younger patients treated with conventional 3+7 regimen. AML arising from a previous myelodisplastic syndrome (s-AML) and therapy-related AML (t-AML) are usually under-represented in trial involving younger patients and are unlikely to respond to conventional induction. Few data are therefore available on the kinetics and the prognostic value of MRD in elderly s- AML and t-AML patients, particularly in the context of alternative induction regimens. Aims: We evaluated MRD in a cohort of elderly s-AML or t-AML patients receiving induction therapy either with a fludarabine-containing regimen or CPX-351, in order to compare the probability of achieving MRD negativity, to disclose the prognostic value of MRD in this setting and to define the best time-points for MRD assessments. Methods: A total of 136 elderly (>60 year, median age 67, range 60-75) patients were analyzed in this study. Patients were treated between January 2005 and January 2020 in our Center, either with CPX-351 (n=35) or fludarabine- high dose cytarabine-idarubicin (FLAI), with (n=72) or without (n =29) gemtuzumab-ozogamicin (GO). MRD was retrospectively analyzed in all patients achieving hematological complete remission (CR) with both MFC and WT1 expression levels.All patients were affected by s-AML or t-AML, defined according to the WHO 2016 criteria. Results: After induction, CR was achieved in 83 patients (61%). CR rate was 28/35 in patients treated with CPX-351 (80%), significantly higher when compared to patients receiving FLAI (55/101, 54.5%, p Moreover, MRD showed significant prognostic value in terms of Overall Survival in all treatment group (2-year OS of 74 and 36% in patients with or without residual MFC MRD after induction, respectively, p Conclusion: In conclusion MRD assessment retains a strong prognostic value and may help to identify patients with suboptimal response to treatment. The higher rate of MRD negativity observed with CPX-351 may be related with a more efficient anti-leukemic activity of the drug in this particular setting. The evaluation of MRD with both MFC and WT1-based assessment lead to superimposable conclusions and allowed us to obtain MRD data from virtually all AML patients treated in the selected time period. Disclosures No relevant conflicts of interest to declare.

Acute myeloid leukemia with biallelic mutation of CEBPA (CEBPA-dm AML) is a distinct good prognosis entity recognized by WHO 2016 classification. However, testing for CEBPA mutation is challenging, due to the intrinsic characteristics of the mutation itself. Indeed, molecular analysis cannot be performed with NGS technique and requires Sanger sequencing. The association of recurrent mutations or translocations with specific immunophenotypic patterns has been already reported in other AML subtypes. The aim of this study was the development of a specific cytofluorimetric score (CEBPA-dm score), in order to distinguish patients who are unlikely to harbor the mutation. To this end, the correlation of CEBPA-dm score with the presence of the mutation was analyzed in 50 consecutive AML patients with normal karyotype and without NPM1 mutation (that is mutually exclusive with CEBPA mutation). One point each was assigned for expression of HLA DR, CD7, CD13, CD15, CD33, CD34 and one point for lack of expression of CD14. OS was not influenced by sex, age and CEBPA-dm score. Multivariate OS analysis showed that CEBPA-dm (p 0.02) and FLT3-ITD (p 0.01) were the strongest independent predictors of OS. With a high negative predictive value (100%), CEBPA-dm score6 was able to identify patients who are unlikely to have the mutation. Therefore, the application of this simple score might optimize the use of expensive and time-consuming diagnostic and prognostic assessment in the baseline work up of AML patients.

Background: The presence of FLT3 "internal tandem duplication" (FLT3-ITD) mutation is associated with poor prognosis in acute myeloid leukemia (AML). However, the concomitant presence of NPM1 mutation (NPM1-mut) partially overcomes the negative prognostic impact of FLT3-ITD, which is also modulated by FLT3-ITD/wild-type allelic ratio. NPM1 and FLT3 mutational status assessment is strongly recommended for risk stratificationat diagnosis by the last European Leukemia Net (ELN) guidelines. Aims: To investigate the efficacy of an intensive fludarabine-containing induction regimen (FLAI) for fit, de novo AML patients according to NPM1 and FLT3-ITD mutational status. Methods: One-hundred and sixteen consecutive AML patients, treated in 3 Hematology Italian centers from January 2008 to January 2018, were included in this analysis. Twenty five patients showed isolated FLT3-ITD, 39 concomitant FLT3-ITD and NPM1-mutation and 52 isolated NPM-1-mutation.Median age was 52 yrs (range: 18-65 years). All patients received fludarabine, high dose cytarabine-based induction (fludarabine 30 mg/sqm and ARA-C 2g/sqm ondays 1 to 5 plus idarubicin 10 mg/sqm on days 1-3-5). For patients achieving CR fludarabine was omitted on II induction course and idarubicin dose was increased to 12 mg/sqm. Before2017 patients with isolated FLT3-ITD mutation were scheduled to receive allogeneic bone marrow transplantation (BMT) in first complete remission regardless of allelic burden whereas after 2017 only patients with high allelic burden received BMT in 1st CR. Minimal residual disease was evaluated on marrow samples using multicolor flow-cytometry (MFC)or NPM1 expression levels. Negative MFC-MRD wasdefined by the presence of less than 25 clustered leukemic cells/105 total events (threshold of 0.025% residual leukemic cells, Minetto et. al, BJH 2019). NPM1mutation (NPM1-A, B and D) was measured using Muta Quant Kit Ipsogen from Qiagen. FLT3-ITD allelic burden was available in31/64 of FLT3-ITD patients. Results: Overall 60-days mortality was 4%. After two induction cycles, 101 patients achieved CR (87%). Thirty-three/101 (33%) CR patients underwent BMT in first CR. After a median follow up of 61 months, 3-year overall survival (OS) was 56.8% (median not reached). In univariate analysis OS duration was favorably affected by age Conclusion: Despite the potential bias due to the retrospective nature of the analysis, our data indicate that intensive fludarabine-high dose cytarabine-based induction exerts a strong anti-leukemic efficacy in younger AML patients carrying NPM1 mutation irrespectively of FLT3 mutational status.Thus, the synergism of fludarabine and cytarabine seems to affect the intrinsic chemosensitivity of NPM1-mut leukemic cells, overcoming the negative impact of FLT3-ITD. Moreover, our data suggest the strong prognostic impact on survival of MRD clearance and question the role of BMT in I CR in this setting of patients. Figure 1 Disclosures Candoni: Gilead: Honoraria, Speakers Bureau; Celgene: Honoraria; Pfizer: Honoraria; Janssen: Honoraria; Merck SD: Honoraria, Speakers Bureau. Bocchia:Incyte: Honoraria; Novartis: Honoraria; BMS: Honoraria.