Multiparameter flow cytometry in the evaluation of myelodysplasia: Analytical issues: Recommendations from the European LeukemiaNet/International Myelodysplastic Syndrome Flow Cytometry Working Group.

Multiparameter flow cytometry (MFC) is one of the essential ancillary methods in bone marrow (BM) investigation of patients with cytopenia and suspected myelodysplastic syndrome (MDS). MFC can also be applied in the follow-up of MDS patients undergoing treatment. This document summarizes recommendations from the International/European Leukemia Net Working Group for Flow Cytometry in Myelodysplastic Syndromes (ELN iMDS Flow) on the analytical issues in MFC for the diagnostic work-up of MDS. Recommendations for the analysis of several BM cell subsets such as myeloid precursors, maturing granulocytic and monocytic components and erythropoiesis are given. A core set of 17 markers identified as independently related to a cytomorphologic diagnosis of myelodysplasia is suggested as mandatory for MFC evaluation of BM in a patient with cytopenia. A myeloid precursor cell (CD34+ CD19- ) count >3% should be considered immunophenotypically indicative of myelodysplasia. However, MFC results should always be evaluated as part of an integrated hematopathology work-up. Looking forward, several machine-learning-based analytical tools of interest should be applied in parallel to conventional analytical methods to investigate their usefulness in integrated diagnostics, risk stratification, and potentially even in the evaluation of response to therapy, based on MFC data. In addition, compiling large uniform datasets is desirable, as most of the machine-learning-based methods tend to perform better with larger numbers of investigated samples, especially in such a heterogeneous disease as MDS.

Clinical application of flow cytometry in patients with unexplained cytopenia and suspected myelodysplastic syndrome: A report of the European LeukemiaNet International MDS-Flow Cytometry Working Group.

This article discusses the rationale for inclusion of flow cytometry (FCM) in the diagnostic investigation and evaluation of cytopenias of uncertain origin and suspected myelodysplastic syndromes (MDS) by the European LeukemiaNet international MDS Flow Working Group (ELN iMDS Flow WG). The WHO 2016 classification recognizes that FCM contributes to the diagnosis of MDS and may be useful for prognostication, prediction, and evaluation of response to therapy and follow-up of MDS patients.

Flow cytometric analysis of myelodysplasia: Pre-analytical and technical issues-Recommendations from the European LeukemiaNet.

BACKGROUND: Flow cytometry (FCM) aids the diagnosis and prognostic stratification of patients with suspected or confirmed myelodysplastic syndrome (MDS). Over the past few years, significant progress has been made in the FCM field concerning technical issues (including software and hardware) and pre-analytical procedures. METHODS: Recommendations are made based on the data and expert discussions generated from 13 yearly meetings of the European LeukemiaNet international MDS Flow working group. RESULTS: We report here on the experiences and recommendations concerning (1) the optimal methods of sample processing and handling, (2) antibody panels and fluorochromes, and (3) current hardware technologies. CONCLUSIONS: These recommendations will support and facilitate the appropriate application of FCM assays in the diagnostic workup of MDS patients. Further standardization and harmonization will be required to integrate FCM in MDS diagnostic evaluations in daily practice.

Next Generation Cytogenetics in Myeloid Hematological Neoplasms: Detection of CNVs and Translocations.

Conventional cytogenetics are the gold standard for the identification of chromosomal alterations recurrent in myeloid neoplasms. Some next-generation sequencing (NGS) panels are designed for the detection of copy number variations (CNV) or translocations; however, their use is far from being widespread. Here we report on the results of a commercial panel including frequent mutations, CNVs and translocations in myeloid neoplasms. Frequent chromosomal alterations were analyzed by NGS in 135 patients with myeloid neoplasms and three with acute lymphoblastic leukemia. NGS analysis was performed using the enrichment-capture Myeloid Neoplasm-GeneSGKit (Sistemas Genómicos, Spain) gene panel including 35 genes for mutational analysis and frequent CNVs and translocations. NGS results were validated with cytogenetics and/or MLPA when possible. A total of 66 frequent alterations included in NGS panel were detected, 48 of them detected by NGS and cytogenetics. Ten of them were observed only by cytogenetics (mainly trisomy 8), and another eight only by NGS (mainly deletion of 12p). Aside from this, 38 secondary CNVs were detected in any of the genes included mainly for mutational analysis. NGS represents a reliable complementary source of information for the analysis of CNVs and translocations. Moreover, NGS could be a useful tool for the detection of alterations not observed by conventional cytogenetics.

Phase I First-in-Human Dose Escalation Study of the oral SF3B1 modulator H3B-8800 in myeloid neoplasms.

We conducted a phase I clinical trial of H3B-8800, an oral small molecule that binds Splicing Factor 3B1 (SF3B1), in patients with MDS, CMML, or AML. Among 84 enrolled patients (42 MDS, 4 CMML and 38 AML), 62 were red blood cell (RBC) transfusion dependent at study entry. Dose escalation cohorts examined two once-daily dosing regimens: schedule I (5 days on/9 days off, range of doses studied 1-40 mg, n = 65) and schedule II (21 days on/7 days off, 7-20 mg, n = 19); 27 patients received treatment for ≥180 days. The most common treatment-related, treatment-emergent adverse events included diarrhea, nausea, fatigue, and vomiting. No complete or partial responses meeting IWG criteria were observed; however, RBC transfusion free intervals >56 days were observed in nine patients who were transfusion dependent at study entry (15%). Of 15 MDS patients with missense SF3B1 mutations, five experienced RBC transfusion independence (TI). Elevated pre-treatment expression of aberrant transcripts of Transmembrane Protein 14C (TMEM14C), an SF3B1 splicing target encoding a mitochondrial porphyrin transporter, was observed in MDS patients experiencing RBC TI. In summary, H3B-8800 treatment was associated with mostly low-grade TAEs and induced RBC TI in a biomarker-defined subset of MDS.

Cost-Effectiveness Analysis of Gemtuzumab Ozogamicin for First-Line Treatment of Patients with Cd-33 Positive Acute Myeloid Leukaemia in Spain.

OBJECTIVE: To assess the incremental cost-utility ratio (ICUR) of gemtuzumab ozogamicin (GO) + standard of care (SOC) vs SOC alone for treatment of patients with de novo AML from a Spanish Health Service perspective. METHODS: A cohort state-transition model, with 12 health-states, was used to estimate the lifetime accumulated cost and benefits in terms of quality-adjusted-life-years (QALYs) in AML patients with favourable, intermediate, and unknown cytogenetic profiles. Patient profile was defined based on the ALFA-0701 trial. Therapeutic regimens were defined by 5 haematologists. SOC was assumed to be idarubicin and cytarabine, the combination most used in Spain. QALYs were estimated by applying utilities for the time spent by the cohort in each health-state and utility decrements associated with adverse events (AE). Total cost (€,2020) included drug-acquisition, hematologic stem-cell transplantation, disease management, AE management and end-of-life costs. Unit costs were derived from local databases. All parameters were validated by haematologist. Costs and outcomes were discounted (3%/year). RESULTS: Higher cost/patient (€177,618 vs €151,434) and greater QALYs (5,70 vs 4,62) were obtained with GO+SOC vs SOC. The ICUR was €24,203/QALY gained. CONCLUSION: This simulation suggests that GO + SOC could be a cost-effective option for treatment of patients with de novo AML in first line.

Clinical utility of targeted next-generation sequencing for the diagnosis of myeloid neoplasms with germline predisposition.

Myeloid neoplasms (MN) with germline predisposition (MNGP) are likely to be more common than currently appreciated. Many of the genes involved in MNGP are also recurrently mutated in sporadic MN. Therefore, routine analysis of gene panels by next-generation sequencing provides an effective approach to detect germline variants with clinical significance in patients with hematological malignancies. Gene panel sequencing was performed in 88 consecutive and five nonconsecutive patients with MN diagnosis. Disease-causing germline mutations in CEBPα, ASXL1, TP53, MPL, GATA2, DDX41, and ETV6 genes were identified in nine patients. Six out of the nine patients with germline variants had a strong family history. These patients presented great heterogeneity in the age of diagnosis and phenotypic characteristics. In our study, there were families in which all the affected members presented the same subtype of disease, whereas members of other families presented various disease phenotypes. This intrafamiliar heterogeneity suggests that the acquisition of particular somatic variants may drive the evolution of the disease. This approach enabled high-throughput detection of MNGP in patients with MN diagnosis, which is of great relevance for both the patients themselves and the asymptomatic mutation carriers within the family. It is crucial to make a proper diagnosis of these patients to provide them with the most suitable treatment, follow-up, and genetic counseling.

Imetelstat Achieves Meaningful and Durable Transfusion Independence in High Transfusion-Burden Patients With Lower-Risk Myelodysplastic Syndromes in a Phase II Study.

PURPOSE: Patients with lower-risk (LR) myelodysplastic syndromes (MDS) who are RBC transfusion dependent and have experienced relapse after or are refractory to erythropoiesis-stimulating agent (ESA) have limited treatment options. High telomerase activity and human telomerase reverse-transcription expression in clonal hematopoietic cells have been reported in patients with MDS. Imetelstat, a first-in-class competitive inhibitor of telomerase enzymatic activity, targets cells with active telomerase. We report efficacy, safety, and biomarker data for patients with LR MDS who are RBC transfusion dependent and who were relapsed/refractory to ESAs. PATIENTS AND METHODS: In this two-part phase II/III study (MDS3001), the primary end point was 8-week RBC transfusion independence (TI) rate, with key secondary end points of 24-week RBC TI rate, TI duration, and hematologic improvement-erythroid. RESULTS: Data from the phase II part of the study are reported. Of 57 patients enrolled and treated (overall population), 38 were non-del(5q) and hypomethylating agent and lenalidomide naïve (subset population). The 8- and 24-week RBC TI rates in the overall population were 37% and 23%, respectively, with a median TI duration of 65 weeks. In the subset population, 8- and 24-week RBC TI rates were 42% and 29%, respectively, with a median TI duration of 86 weeks. Eight-week TI rate was observed across all subgroups evaluated. Cytogenetic and mutational data revealed a reduction of the malignant clones, suggesting disease modification activity. The most common adverse events were cytopenias, typically reversible within 4 weeks. CONCLUSION: Imetelstat treatment results in a meaningful, durable TI rate across a broad range of heavily transfused patients with LR MDS who are ineligible for or relapsed/refractory to ESAs. Biomarker analyses indicated effects on the mutant malignant clone.

Next-Generation Sequencing Improves Diagnosis, Prognosis and Clinical Management of Myeloid Neoplasms.

Molecular diagnosis of myeloid neoplasms (MN) is based on the detection of multiple genetic alterations using various techniques. Next-generation sequencing (NGS) has been proved as a useful method for analyzing many genes simultaneously. In this context, we analyzed diagnostic samples from 121 patients affected by MN and ten relapse samples from a subset of acute myeloid leukemia patients using two enrichment-capture NGS gene panels. Pathogenicity classification of variants was enhanced by the development and application of a custom onco-hematology score. A total of 278 pathogenic variants were detected in 84% of patients. For structural alterations, 82% of those identified by cytogenetics were detected by NGS, 25 of 31 copy number variants and three out of three translocations. The detection of variants using NGS changed the diagnosis of seven patients and the prognosis of 15 patients and enabled us to identify 44 suitable candidates for clinical trials. Regarding AML, six of the ten relapsed patients lost or gained variants, comparing with diagnostic samples. In conclusion, the use of NGS panels in MN improves genetic characterization of the disease compared with conventional methods, thus demonstrating its potential clinical utility in routine clinical testing. This approach leads to better-adjusted treatments for each patient.

Multicenter comparison of CD34+ myeloid cell count by flow cytometry in low-risk myelodysplastic syndrome. Is it feasible?

BACKGROUND: Accuracy of bone marrow (BM) blast count in low-risk myelodysplastic syndromes (MDS) still remains a challenge though it is essential for prognosis. We investigated whether the enumeration of CD34+ myeloid cells by flow cytometry immunophenotyping (FCI) could be used as a consistent parameter for clinical MDS studies. METHODS: Six clinical centers entered the study and information on their FCI protocols was recorded. Sixty-seven flow cytometry listmodes from BM samples of patients with low-risk MDS with <5% BM blasts were exchanged among participants in two different rounds. Interlaboratory variations on the quantification of CD34+ myeloid cells were calculated and strategies to solve differences were evaluated. RESULTS: An overall "very good" agreement on CD34+ cell count among participants (intraclass correlation coefficient = 0.720) was observed, but agreement was "low" in 22 files. No single parameter could fully explain all discrepancies, but 3 technical issues were identified as relevant: the use of the CD34/CD45/CD117/HLA-DR mAb combination, acquisition of ≥50,000 events and a low percentage of debris/aggregates. The frequency of discordant results increased with the accumulation of pitfalls (none, 16%; 1 pitfall, 40%; 2 pitfalls, 83%; P = 0.006). Finally, the use of a common gating strategy for analysis increased the percentage of files with "very good" agreement to 100%. CONCLUSIONS: Prevention of specific technical pitfalls is mandatory to reach a good reproducibility of CD34+ cell count among centers. These recommendations set the basis for laboratory standardization and enable the use of CD34+ cell enumeration as additional information in low-risk MDS patients. © 2017 International Clinical Cytometry Society.

Interobserver variance in myelodysplastic syndromes with less than 5 % bone marrow blasts: unilineage vs. multilineage dysplasia and reproducibility of the threshold of 2 % blasts.

Previous studies have shown the reproducibility of the 2008 World Health Organization (WHO) classification in myelodysplastic syndromes (MDS), especially when multilineage dysplasia or excess of blasts are present. However, there are few data regarding the reproducibility of MDS with unilineage dysplasia. The revised International Prognostic Scoring System R-IPSS described two new morphological categories, distinguishing bone marrow (BM) blast cell count between 0-2 % and >2- < 5 %. This distinction is critical for establishing prognosis, but the reproducibility of this threshold is still not demonstrated. The objectives of our study were to explore the reliability of the 2008 WHO classification, regarding unilineage vs. multilineage dysplasia, by reviewing 110 cases previously diagnosed with MDS, and to study whether the threshold of ≤2 % BM blasts is reproducible among different observers. We used the same methodology as in our previous paper [Font et al. (2013) Ann Hematol 92:19-24], by encouraging investigators to include patients with <5 % BM blasts. Samples were collected from 11 hospitals and were evaluated by 11 morphologists. Each observer evaluated 20 samples, and each sample was analyzed independently by two morphologists. Discordance was observed in 36/108 suitable cases (33 %, kappa test 0.503). Diagnosis of MDS with unilineage dysplasia (refractory cytopenia with unilineage dysplasia (RCUD), refractory anemia with ring sideroblasts (RARS) or unclassifiable MDS) was assessed in 33 patients, by either of the two observers. We combined this series with the cases with RCUD or RARS included in our 2013 paper, thus obtaining 50 cases with unilineage dysplasia by at least one of the observers. The whole series showed very low agreement regarding RCUD (5/23, 21 %) and RARS (5/28, 18 %). Regarding BM blast count, the threshold of ≤2 % was not reproducible (discordance rate 32/108 cases, kappa test 0.277). Our study shows that among MDS WHO 2008 categories, interobserver discordance seems to be high in cases with unilineage dysplasia. We also illustrate that the threshold of ≤2 % BM blasts as settled by the R-IPSS may be not easy to reproduce by morphologists in real practice.

Rationale for the clinical application of flow cytometry in patients with myelodysplastic syndromes: position paper of an International Consortium and the European LeukemiaNet Working Group.

An international working group within the European LeukemiaNet gathered, aiming to determine the role of flow cytometry (FC) in myelodysplastic syndromes (MDS). It was agreed that FC has a substantial application in disease characterization, diagnosis and prognosis. FC may also be useful in predicting treatment responses and monitoring novel and standard therapeutic regimens. In this article the rationale is discussed that flow cytometry should be integrated as a part of diagnostic and prognostic scoring systems in MDS.

Azacitidine for the treatment of patients with acute myeloid leukemia with 20%-30% blasts and multilineage dysplasia.

Azacitidine is approved in the EU for the treatment of adult patients who are not candidates for allogeneic stem cell transplantation, and who have intermediate-2 risk or high-risk myelodysplastic syndromes, according to the International Prognostic Scoring System. The approval includes the treatment of patients with acute myeloid leukemia (AML) with 20%-30% blasts and multilineage dysplasia, according to the World Health Organization (WHO) classification. This review focuses on the outcomes with azacitidine in this latter group of patients, previously classified as refractory anemia with excess of blasts in transformation, as defined by the French-American-British classification criteria. The main clinical evidence is based on the results of two large phase III clinical trials (Cancer and Leukemia Group B 9221, and AZA-001). The AZA-001 trial shows azacitidine significantly prolongs median overall survival in older patients with low marrow blasts (20%-30%) according to WHO-defined AML, and significantly improved several patient morbidity measures, compared with conventional care regimens. In addition, the review examines the results of azacitidine in combination with other treatments currently used in AML.

Acute myeloblastic leukemia.

Myelodysplastic syndromes (MDS) are a group of clonal cell disorders characterized by maturation defects, resulting in ineffective hematopoiesis. They often transform to acute myeloblastic leukemia (AML), which is difficult to treat and carries a dismal prognosis. Azacitidine is a hypomethylating agent approved for the treatment of patients with MDS, including AML with 20% to 30% bone marrow blasts, according to World Health Organization classification. The three patient cases presented in this paper exemplify the spectrum of antitumor activity and toxicity of azactidine in patients where MDS transformed to AML.

Standardization of flow cytometry in myelodysplastic syndromes: report from the first European LeukemiaNet working conference on flow cytometry in myelodysplastic syndromes.

The myelodysplastic syndromes are a group of clonal hematopoietic stem cell diseases characterized by cytopenia(s), dysplasia in one or more cell lineages and increased risk of evolution to acute myeloid leukemia (AML). Recent advances in immunophenotyping of hematopoietic progenitor and maturing cells in dysplastic bone marrow point to a useful role for multiparameter flow cytometry (FCM) in the diagnosis and prognostication of myelodysplastic syndromes. In March 2008, representatives from 18 European institutes participated in a European LeukemiaNet (ELN) workshop held in Amsterdam as a first step towards standardization of FCM in myelodysplastic syndromes. Consensus was reached regarding standard methods for cell sampling, handling and processing. The group also defined minimal combinations of antibodies to analyze aberrant immunophenotypes and thus dysplasia. Examples are altered numbers of CD34(+) precursors, aberrant expression of markers on myeloblasts, maturing myeloid cells, monocytes or erythroid precursors and the expression of lineage infidelity markers. When applied in practice, aberrant FCM patterns correlate well with morphology, the subclassification of myelodysplastic syndromes, and prognostic scoring systems. However, the group also concluded that despite strong evidence for an impact of FCM in myelodysplastic syndromes, further (prospective) validation of markers and immunophenotypic patterns are required against control patient groups as well as further standardization in multi-center studies. Standardization of FCM in myelodysplastic syndromes may thus contribute to improved diagnosis and prognostication of myelodysplastic syndromes in the future.

Fluorescence in situ hybridization improves the detection of 5q31 deletion in myelodysplastic syndromes without cytogenetic evidence of 5q-.

BACKGROUND: More than 50% of patients with myelodysplastic syndromes present cytogenetic aberrations at diagnosis. Partial or complete deletion of the long arm of chromosome 5 is the most frequent abnormality. The aim of this study was to apply fluorescence in situ hybridization of 5q31 in patients diagnosed with de novo myelodysplastic syndromes in whom conventional banding cytogenetics study had shown a normal karyotype, absence of metaphases or an abnormal karyotype without evidence of del(5q). DESIGN AND METHODS: We performed fluorescence in situ hybridization of 5q31 in 716 patients, divided into two groups: group A patients (n=637) in whom the 5q deletion had not been detected at diagnosis by conventional banding cytogenetics and group B patients (n=79), in whom cytogenetic analysis had revealed the 5q deletion (positive control group). RESULTS: In group A (n=637), the 5q deletion was detected by fluorescence in situ hybridization in 38 cases (5.96%). The majority of positive cases were diagnosed as having the 5q- syndrome. The deletion was mainly observed in cases in which the cytogenetics study had shown no metaphases or an aberrant karyotype with chromosome 5 involved. In group B (n=79), the 5q deletion had been observed by cytogenetics and was confirmed to be present in all cases by fluorescence in situ hybridization of 5q31. CONCLUSIONS: Fluorescence in situ hybridization of 5q31 detected the 5q deletion in 6% of cases without clear evidence of del(5q) by conventional banding cytogenetics. We suggest that fluorescence in situ hybridization of 5q31 should be performed in cases of a suspected '5q- syndrome' and/or if the cytogenetic study shows no metaphases or an aberrant karyotype with chromosome 5 involved (no 5q- chromosome).

Immunophenotype in chronic myelomonocytic leukemia: is it closer to myelodysplastic syndromes or to myeloproliferative disorders?

Chronic myelomonocytic leukemia (CMML) is a heterogeneous disease balanced between myelodysplastic syndromes (MDS) and myeloproliferative disorders (MPD). We used flow cytometry to describe and compare the immunophenotypic profile of 20 patients with CMML, 38 patients with MDS, and 20 patients with MPD. CMML and MDS only showed statistically significant differences (P<0.05) in CD56 monocyte expression. CMML and MPD showed significant differences in CD45 myeloid distribution, myeloid antigenic profile, CD56 and CD2 monocyte expression, and B-cell development. These data support the classic concept of CMML as part of MDS diseases and encourage including immunophenotyping among the studies to be performed in these diseases.