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Gemtuzumab ozogamicin (GO) is a conjugate of a monoclonal antibody and calicheamicin, which has been reapproved for the treatment of acute myeloid leukemia (AML). AML patients with the CD33 rs12459419 CC genotype might benefit from the addition of GO to intensive treatment in contrast to patients with CT/TT genotypes. Nevertheless, contradictory results have been reported. We sought to shed light on the prediction of GO response in AML patients with rs12459419 polymorphism who were treated with GO in the consolidation ( n = 70 ) or reinduction ( n = 20 ) phase. The frequency distribution of the rs12459419 polymorphism in the complete cohort of patients was 44.4% ( n = 40 ), 50% ( n = 45 ), and 5.6% ( n = 5 ) for CC, CT, and TT genotypes, respectively. Regarding the patients treated with GO for consolidation, we performed a Kaplan-Meier analysis of overall survival and relapse-free survival according to the rs12459419 polymorphism (CC vs. CT/TT patients) and genetic risk using the European Leukemia Net (ELN) 2010 risk score. We also carried out a Cox regression analysis for the prediction of overall survival, with age and ELN 2010 as covariates. We found no statistical significance in the univariate or multivariate analysis. Additionally, we performed a global Kaplan-Meier analysis for the patients treated with GO for reinduction and did not find significant differences; however, our cohort was too small to draw any conclusion from this analysis. The use of GO in consolidation treatment is included in the approval of the compound; however, evidence regarding its efficacy in this setting is lacking. Rs12459419 polymorphism could help in the selection of patients who might benefit from GO. Regrettably, in our cohort, the rs12459419 polymorphism does not seem to be an adequate tool for the selection of patients who might benefit from the addition of GO in consolidation cycles.

Gemtuzumab ozogamicin (GO) is a conjugate of a monoclonal antibody and calicheamicin, which has been reapproved for the treatment of acute myeloid leukemia (AML). AML patients with the

BCR-ABL1/ABL1 p210 measurement by quantitative polymerase chain reaction (qPCR) is used worldwide to monitor the molecular response in chronic myeloid leukemia (CML) patients. Droplet digital polymerase chain reaction (ddPCR) seems to show a greater sensitivity than qPCR, probably due to the high number of replicates analyzed in ddPCR for the comparison. Additionally, in a recently published comparison, ddPCR measurements were not adequately transformed into International Scale (IS). We have analyzed 50 CML patients and ten non-CML donors in parallel by qPCR and ddPCR. To the best of our knowledge, this is the first study comparing both techniques under similar conditions, with BCR-ABL1/ABL1 measurements performed via both techniques transformed into IS. Qualitative and quantitative comparisons showed excellent results. The qualitative correlation showed a Kappa index of 0.94 (95% confidence interval [CI] 0.90–0.98) (P

FLT3-ITD mutations are detected in approximately 25% of newly diagnosed adult acute myeloid leukemia (AML) patients and confer an adverse prognosis. The FLT3-ITD allelic ratio has clear prognostic value. Nevertheless, there are numerous manuscripts with contradictory results regarding the prognostic relevance of the length and insertion site (IS) of the FLT3-ITD fragment. We aimed to assess the prognostic impact of these variables on the complete remission (CR) rates, overall survival (OS) and relapse-free survival (RFS) of AML patients with FLT3-ITDmutations. We studied the FLT3-ITD length of 362 adult AML patients included in the PETHEMA AML registry. We tried to validate the thresholds of ITD length previously published (i.e., 39 bp and 70 bp) in intensively treated AML patients (n = 161). We also analyzed the mutational profile of 118 FLT3-ITD AML patients with an NGS panel of 39 genes and correlated mutational status with the length and IS of ITD. The AUC of the ROC curve of the ITD length for OS prediction was 0.504, and no differences were found when applying any of the thresholds for OS, RFS or CR rate. Only four out of 106 patients had ITD IS in the TKD1 domain. Our results, alongside previous publications, confirm that FLT3-ITD length lacks prognostic value and clinical applicability.

We retrospectively evaluated 2879 hospitalized COVID-19 patients from four hospitals to evaluate the ability of demographic data, medical history, and on-admission laboratory parameters to predict in-hospital mortality. Association of previously published risk factors (age, gender, arterial hypertension, diabetes mellitus, smoking habit, obesity, renal failure, cardiovascular/ pulmonary diseases, serum ferritin, lymphocyte count, APTT, PT, fibrinogen, D-dimer, and platelet count) with death was tested by a multivariate logistic regression, and a predictive model was created, with further validation in an independent sample. A total of 2070 hospitalized COVID-19 patients were finally included in the multivariable analysis. Age 61–70 years (pp80 years (pp2 ULN (p= 0.003; OR: 1.79; 95%CI: 1.22 to 2.62), and prolonged PT (p

Introduction Acute myeloid leukemia (AML) is a clonal disease with a reduced life expectancy due to a high relapse rate. One explanation is that leukemic stem cells (LSC) evade the action of conventional chemotherapy due to their quiescent state. Several mechanisms have been proposed that regulate their quiescence, however, by analogy with normal hematopoietic stem cells, a key role may be carried out by the signaling pathways Notch and Hedgehog (Hh). The objectives of this study are to analyze the role of Notch and Hh pathways in the quiescence of LSC and to verify if the pharmacological inhibition of the Notch and Hh pathways decreases the percentage of quiescent LSC. In this way, LSCs would be sensitized to chemotherapy treatments and the high relapse rate of AML could be reduced. Methods Expression of GLI1, a transcription factor of the Hh signaling pathway and NOTCH Internal Cleaved Domain (NICD) were analyzed in the hematopoietic stem and progenitor cells of four patients diagnosed with AML. The selection of quiescent fraction was performed by flow cytometry using anti-CD34-FITC, anti-CD117-PerCP, anti-CD45PE-Cy7, anti-CD38-APC-Cy7 and anti-KI67-BV510 antibodies. KI67 negative cells were considered quiescent. The activation of NOTCH and Hh pathways was studied using rabbit anti-GLI, anti-NICD primary antibodies and anti-rabbit BV421 secondary antibodies. Results were expressed in median (range) or mean ± standard deviation. Dose-response curves of inhibitors of the Notch pathway (BMS-906024, inhibitor of γ-secretase), Hh pathway (BMS-833923, SMO inhibitor and GANT61, GLI inhibitor), and cytarabine (AraC) were made to study drug potency in the OCI-AML3 cell line. We also analyzed its synergistic behavior in combination with Arac by calculating the combination index (CI) of each of them. These experiments were conducted in triplicate and values were expressed as the mean ± standard deviation. Finally, the effect of BMS-833923 and BMS-906024 on the quiescence of the CD34+CD38- cells of two patients diagnosed with AML was studied by flow cytometry. The paired samples t-test was used in the statistical analysis of GLI and NICD expression between G0 and proliferating cells and in the statistical analysis of the decrease of quiescent cells due to Notch and Hh inhibitors. Results First of all, hematopoietic and progenitor cells were quantified in four AML patients: the median of the percentage of CD34+CD38- cells with respect to total cells in the bone marrow of the AML patient studied was 1.1% (range: 0.12%-9.05%), within which 71.50% (range: 64.30%-88.43%) are quiescent. Interestingly, we found a trend for a higher expression of NOTCH signaling pathway in the proliferating CD34+CD38- cells (relative median fluorescent intensity (MFI) = 1.91 (range: 1.51-3.34)) compared to the quiescent fraction (relative MFI=1.55 (range: 1.18-1.94); p=0.105). But no differences were found in expression of GLI1. Before studying the effect on cellular quiescence of Notch and Hh inhibitors in monotherapy and in combination with AraC, we evaluated their effect on cell viability. The most potent drug studied was AraC (IC50 = 4.055 μM), followed by inhibitors of the Hh pathway (IC50 BMS-833923 = 5.041 μM; IC50 GANT61 = 7.042 μM) on the OCI-AML3 cell line. In contrast, the γ-secretase inhibitor (BMS-906024) showed no effect. Moreover, it was found that the combination 0.8 μM AraC plus 8 μM BMS-833923 was the most synergistic (CI = 0.53, 15% viability with respect to DMSO control). Subsequently, the effect of the SMO inhibitor on the quiescent CD34+CD38- cells of two patients diagnosed with CD34+ AML was analyzed: BMS-833923 decreased the percentage of quiescent CD34+CD38- cells by 88.5±16.3% in monotherapy (p=0.083) and in presence of AraC by 85.8 ± 21.2% (p=0.113) (figure 1). Conclusion The use of SMO inhibitors for the treatment of AML is promising because it increases the sensitivity of leukemic cells to chemotherapy and facilitates their action by reducing the percentage of quiescent LSC. This could mean a decrease in the probability of relapse in patients with AML treated with Hh inhibitors. These results were derived from an ongoing project and more patients are being studied in order to confirm the explained results. This work is partially funded by the Madrid Association of Hematology and Hemotherapy. Disclosures No relevant conflicts of interest to declare.