Hematologic Neoplasms Research Articles

Role of Cytogenetics and Fluorescence In Situ Hybridization in the Laboratory Workup of Acute Myeloid Leukemias

AbstractA new understanding of acute myeloid leukemia as a varied group of unique biologic entity has emerged, as a result of the identification of various chromosomal aberrations and their association with clinical prognosis and diagnosis. Following induction treatment, cytogenetic examination can establish the presence of any residual malignant cells, it's recurrence, clonal evolution if any, or the formation of novel abnormalities. The G-banded karyotype has been the gold standard method for detecting all of these aberrations for years. The capacity to examine the entire genome through karyotype analysis quickly enabled the detection of deletions, duplications, and structural rearrangements across every chromosome, and the more frequent ones were associated with particular aberrant clinical symptoms. Fluorescence in situ hybridization (FISH) is a sensitive technology that aids in differential diagnosis or therapeutic planning and provides rapid results. Furthermore, the combination of cytogenetic and molecular profiling enables a more precise evaluation of disease prognosis, diagnosis, classification, risk stratification, and patient treatment. Interphase FISH analysis, in conjunction with G-banded chromosomal analysis, can be used as a major testing tool for the evaluation of hematological neoplasms. For accurate and consistent descriptions of genomic changes identified by karyotyping and FISH, a specified terminology is necessary. The International System for Human Cytogenomic Nomenclature is the main source and provides instructions for documenting cytogenetic and molecular findings in laboratory reports. This review discusses the two methods, karyotyping and FISH, their advantages and limitations, sample requirements, various FISH probes that are used, nomenclature for results reporting, and the necessary quality control measures.

5-Aza-2′-Deoxycytidine Alters the Methylation Profile of Bortezomib-Resistant U266 Multiple Myeloma Cells and Affects Their Proliferative Potential

Multiple myeloma (MM) is a plasma cell malignancy that accounts for 1% of all cancers and is the second-most-common hematological neoplasm. Bortezomib (BTZ) is a proteasome inhibitor widely implemented in the treatment of MM alone or in combination with other agents. The development of resistance to chemotherapy is one of the greatest challenges of modern oncology. Therefore, it is crucial to discover and implement new adjuvant therapies that can bypass therapeutic resistance. In this paper, we investigated the in vitro effect of methylation inhibitor 5-Aza-2′-deoxycytidine on the proliferative potential of MM cells and the development of resistance to BTZ. We demonstrate that alterations in the DNA methylation profile are associated with BTZ resistance. Moreover, the addition of methylation inhibitor 5-Aza-2′-deoxycytidine to BTZ-resistant MM cells led to a reduction in the proliferation of the BTZ-resistant phenotype, resulting in the restoration of sensitivity to BTZ. However, further in vitro and ex vivo studies are required before adjuvant therapy can be incorporated into existing treatment regimens.

The role of flow cytometry in the classification of myeloid disorders.

The World Health Organization classification (WHO-HAEM5) and the International Consensus Classification (ICC 2022) of myeloid neoplasms are based on the integration of clinical, morphologic, immunophenotypic, and genomic data. Flow cytometric immunophenotyping (FCIP) allows the identification, enumeration, and characterization of hematopoietic cells, and is therefore apowerful tool in the diagnosis, classification, and monitoring of hematological neoplasms. The vast majority of flow cytometry (FCM) studies in chronic myeloid neoplasms focus on its role in myelodysplastic neoplasms (MDS). FCM can also be helpful for the assessment of myeloproliferative neoplasms (MPN) and MDS/MPN, including the early detection of evolving myeloid or lymphoid blast crisis and the characterization of monocytic subsets. The classification of acute myeloid leukemia (AML) is primarily based on cytogenetic and molecular findings; however, FCIP is needed for subclassification of AML, not otherwise specified (NOS; ICC)/AML defined by differentiation (WHO-HAEM5). The main role of FCM in AML remains in making arapid diagnosis and as atool for measurable residual disease monitoring. Machine learning and artificial intelligence approaches can be used to analyze and classify FCM data. This article, based on an invited lecture at the 106th Annual Meeting of the German Society of Pathology in 2023, reviews the role of FCM in the classification of myeloid neoplasms, including recent publications on the application of artificial intelligence.

Evaluation of lifestyle behaviors, anxiety and depression in patients with hematologic disorders.

Patients with hematologic disorders may experience anxiety and depression due to their immunocompromised status and potential side effects of therapies. Healthy lifestyle behaviors might enhance the mental health. To evaluate the association of both separate and clustering pattern lifestyle behaviors with anxiety and depression in hematological patients, healthcare providers can develop future initiatives that respond to the specific needs of this population. A total of 185 patients with hematologic disorders were enrolled in this cross-sectional study. Linear regression analysis was performed to measure the association of separate lifestyles with anxiety and depression. Latent class analysis was further conducted to identify homogeneous and mutually exclusive lifestyle classes, and the logistic regression was then used to assess the relationship between class memberships and symptoms of anxiety and depression. The study found sleep quality was correlated with anxiety and depression. Nevertheless, no association of anxious and depressive symptoms with sitting and exercise, dietary habits, toxicant exposure, drinking, and smoking, in either the overall patient population or patients classified by hematologic neoplasms. Two latent classes of lifestyle behaviors were further identified, but the class memberships were independent of anxiety and depression. The study suggested that promoting sleep quality was a viable intervention for patients with hematologic disorders. However, the clustering pattern of lifestyles may not be a reliable indicator of psychological issues.

Ring Chromosomes in Hematological Malignancies Are Associated with TP53 Gene Mutations and Characteristic Copy Number Variants.

Ring chromosomes (RC) are present in <10% of patients with hematological malignancies and are associated with poor prognosis. Until now, only small cohorts of patients with hematological neoplasms and concomitant RCs have been cytogenetically characterized. Here, we performed a conventional chromosome analysis on metaphase spreads from >13,000 patients diagnosed with hematological malignancies at the Johns Hopkins University Hospital and identified 98 patients with RCs-90 with myeloid malignancies and 8 with lymphoid malignancies. We also performed a targeted Next-Generation Sequencing (NGS) assay, using a panel of 642 cancer genes, to identify whether these patients harbor relevant pathogenic variants. Cytogenetic analyses revealed that RCs and marker chromosomes of unknown origin are concurrently present in most patients by karyotyping, and 93% of patients with NGS data have complex karyotypes. A total of 72% of these individuals have pathogenic mutations in TP53, most of whom also possess cytogenetic abnormalities resulting in the loss of 17p, including the loss of TP53. All patients with a detected RC and without complex karyotypes also lack TP53 mutations but have pathogenic mutations in TET2. Further, 70% of RCs that map to a known chromosome are detected in individuals without TP53 mutations. Our data suggest that RCs in hematological malignancies may arise through different mechanisms, but ultimately promote widespread chromosomal instability.

Lycorine eliminates B-cell acute lymphoblastic leukemia cells by targeting PSAT1 through the serine/glycine metabolic pathway

B-cell acute lymphoblastic leukemia (B-ALL) has been confirmed as the most common malignant hematologic neoplasm among children. A novel antitumor mechanism of lycorine was elucidated in this study. As revealed by the result of this study, lycorine significantly inhibited the growth and proliferation of REH and NALM-6 and induced their apoptosis. The result of the RNA-seq analysis suggested that lycorine targeted PSAT1 of serine/glycine metabolism in B-ALL cells. As indicated by the result of the GSEA analysis, the genes enriched in the amino acid metabolic pathways were down-regulated by lycorine. As revealed by the results of ectopic expression, shRNA knockdown assays, and further liquid-phase tandem mass spectrometry (LC-MS) analysis, lycorine reduced serine/glycine metabolites by down-regulating PSAT1, further disrupting carbon metabolism and eliminating B-ALL cells. Furthermore, lycorine showed a synergistic effect with cytarabine in ALL treatments. Lastly, lycorine significantly down-regulated leukemia progression in the cell line-derived xenograft (CDX) model. In brief, this study has suggested for the first time that lycorine is a promising anti-ALL drug, and a novel amino acid metabolism-associated property of lycorine was identified.

The Clinical Relevance of Selected Cytokines in Newly Diagnosed Multiple Myeloma Patients.

Multiple myeloma (MM) is the second most common hematological neoplasm. Cytokines, chemokines, and their receptors, induced by the microenvironment of MM, participate in tumor growth, the attraction of leukocytes, cell homing, and bone destruction. This study aimed to assess the correlation between the pretreatment serum concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), angiogenic chemokine monocyte chemoattractant protein-1 (MCP-1), and vascular endothelial growth factor (VEGF) and the clinical outcomes and survival of patients newly diagnosed with MM. The study group consisted of 82 individuals. The IL-8 concentration was significantly positively correlated with the age of onset (p = 0.007), the International Staging System (ISS) stage (p = 0.03), the Eastern Cooperative Oncology Group (ECOG) performance status (p < 0.001), the degree of anemia before treatment (p < 0.0001), the degree of kidney disease (p < 0.001), and VEGF (p = 0.0364). Chemotherapy responders had significantly lower concentrations of IL-8 (p < 0.001), IL-6 (p < 0.001), and VEGF (p = 0.04) compared with non-responders. Patients with treatment-induced polyneuropathy had significantly higher levels of IL-8 (p = 0.033). Patients with a high level of IL-6 had a 2-fold higher risk of progression-free survival (PFS) reduction (17 vs. 35 months; HR = 1.89; p = 0.0078), and a more than 2.5-fold higher risk of overall survival (OS) reduction (28 vs. 78 months; HR = 2.62; p < 0.001). High levels of IL-6, IL-8, and VEGF demonstrated significant predictive values for some clinical conditions or outcomes of newly diagnosed MM patients. Patients with an early response to chemotherapy had a significantly lower concentration of these cytokines. A high pretreatment IL-6 concentration was an independent negative prognostic marker for newly diagnosed MM patients.

Meningeal Syndrome as the Debut of Multiple Myeloma, Case Report

Multiple myeloma (MM) is a monoclonal gammopathy characterized by malignant proliferation of plasma cells. Considered the second most common hematological neoplasm. Symptoms result from infiltration of plasma cells and secreted monoclonal proteins or interaction of plasma cells with their microenvironment. The classic CRAB criteria (Hypercalcemia, renal failure, anemia and lytic lesions), with renal failure being one of its most frequent complications, are necessary to establish the diagnosis. Our report presents the case of a man in his seventh decade of life, who presented with meningeal syndrome, which motivated the study approach, reaching the conclusion that this entity was due to a state of immunosuppression secondary to multiple myeloma, whose diagnostic suspicion was a finding that was obtained when doing a comprehensive study of the disease, since reaching the diagnosis in this case was a cause of controversy as it had an unusual presentation. This is a good case to discuss differential diagnoses and teaches us that in medical practice we deal with patients and not with diseases, since these debut in a particular way in each individual.

An Integral R-Banded Karyotype Analysis System of Bone Marrow Metaphases Based on Deep Learning.

Conventional karyotype analysis, which provides comprehensive cytogenetic information, plays a significant role in the diagnosis and risk stratification of hematologic neoplasms. The main limitations of this approach include long turnaround time and laboriousness. Therefore, we developed an integral R-banded karyotype analysis system for bone marrow metaphases, based on deep learning. To evaluate the performance of the internal models and the entire karyotype analysis system for R-banded bone marrow metaphase. A total of 4442 sets of R-banded normal bone marrow metaphases and karyograms were collected. Accordingly, 4 deep learning-based models for different analytic stages of karyotyping, including denoising, segmentation, classification, and polarity recognition, were developed and integrated as an R-banded bone marrow karyotype analysis system. Five-fold cross validation was performed on each model. The whole system was implemented by 2 strategies of automatic and semiautomatic workflows. A test set of 885 metaphases was used to assess the entire system. The denoising model achieved an intersection-over-union (IoU) of 99.20% and a Dice similarity coefficient (DSC) of 99.58% for metaphase acquisition. The segmentation model achieved an IoU of 91.95% and a DSC of 95.79% for chromosome segmentation. The accuracies of the segmentation, classification, and polarity recognition models were 96.77%, 98.77%, and 99.93%, respectively. The whole system achieved an accuracy of 93.33% with the automatic strategy and an accuracy of 99.06% with the semiautomatic strategy. The performance of both the internal models and the entire system is desirable. This deep learning-based karyotype analysis system has potential in a clinical application.

Using Next Generation Sequencing of Flow Cytometry CD Markers and Machine Learning As a Replacement to Flow Cytometry Analysis for the Diagnosis of Hematologic Neoplasms

Introduction: Flow cytometry performs multi-parameter analysis of cells and analyzes surface and intracellular markers for accurate phenotypic characterization of a cell population. Flow cytometry is used extensively in the diagnosis and classification of various hematologic neoplasms. However, analysis of the generated data is time consuming and remains subjective, requiring special skill and experience. Furthermore, some diagnostic classes, such as myeloproliferative neoplasms (MPN) and myelodysplastic syndrome (MDS), are difficult to diagnose using flow cytometry. The RNA levels of the CD markers used in flow cytometry can be reliably quantified using next generation sequencing (NGS). However, when all cells are jointly sequenced, studying subpopulation of cells is lost, which hinders accurate diagnosis. However, machine learning algorithms are capable of multi-marker normalizing and compensate for the loss of subclonal analysis. To validate this assumption, we explored the potential of using the RNA levels of 30 CD markers along with a machine learning algorithm in the differential diagnosis between various types of hematologic neoplasms. Methods: RNA was extracted from fresh bone marrow and peripheral blood samples from 172 acute myeloid leukemia (AML), 369 normal control, 68 MPN, 218 MDS, 93 acute lymphoblastic leukemia (ALL), 74 chronic lymphocytic leukemia (CLL), 38 mantle cell lymphoma, and 83 multiple myeloma cases. The samples were consecutive and collected without selection. RNA sequencing was performed using a targeted hybrid capture panel that included CD1A, CD2, CD3D, CD3E, CD3G, CD4, CD5, CD7, CD8A, CD8B, CD10, CD14, CD19, CD20, CD22, CD33, CD34, CD38, CD40, CD44, CD47, CD68, CD70, CD74, CD79A, CD79B, CD81, CD138, CD200, and CD274 genes. Salmon v1.4.0 software was used for expression quantification (TPM). Machine learning algorithm (random forest) was used for classifying diseases. Two thirds of samples were used for training the random forest algorithm and one third was used for testing. Results: While frequently a diagnosis can be made by simply inspecting the RNA levels of various CD markers, machine learning is needed when the fraction of the neoplastic cells is low. Using machine learning (random forest), diagnosis of most hematologic neoplasms was achieved with high sensitivity and specificity in the testing set. Area under the curve (AUC) was at 0.972 (95% CI: 0.950-0.994) for AML vs. normal, 0.936 (95% CI: 0.898-0.974) for normal vs. MM, 0.965 (95% CI: 0.909-1.00) for mantle vs. CLL, 0.962 (95% CI: 0.907-1.00) for CLL vs. ALL, 0.935 (95% CI: 0.866-1.00) for CLL vs. normal, and 0.964 (95% CI: 0.927-1.00) for AML vs. ALL. Diseases that are difficult to diagnose by routine flow cytometry were diagnosed by RNA expression and machine learning at acceptable accuracy. For example, AUC was at 0.761 (95% CI: 0.689-0.834) for MDS vs. normal, 0.831 (95% CI: 0.762-0.901) for MDS vs. AML, 0.888 (95% CI: 0.822-0.954) for MDS vs. MPN, and 0.785 (95% CI: 0.698-0.872) for MPN vs. normal. Conclusions: This data demonstrates that NGS quantification of RNA from 30 CD markers when combined with machine learning is adequate for reliable diagnosis of various types of hematologic neoplasms. This approach can provide valuable information to distinguish between MPN, MDS, and normal bone marrow that flow cytometry cannot provide. Furthermore, this technology can be automated and less susceptible to human error and practically can be used as a replacement to routine flow cytometry analysis.

Beta-2 Microglobulin As a Seric Marker for Diagnosis of Hematologic Neoplasms in First Contact Consultation with the Hematologist

Introduction Beta-2 microglobulin is a protein component of the Major histocompatibility complex I. Its concentration in blood has been long used as prognostic marker in some hematologic neoplasms, and even used as a tool for surveillance of relapse in other neoplasms. It is frequently elevated in non-Hodgkin lymphoma (NHL), Myelodysplastic syndrome (MDS), myeloma multiple (MM), chronic lymphocytic leukemia (CLL) and other Lymphoproliferative disorders. Although its utility as a diagnostic tool has been poorly described. Aim Describe the blood levels of Beta-2 Microglobulin in patients who are sent without established diagnosis to be evaluated by hematology department and its association with the different definitive diagnosis. Methods We captured information from outpatients who were evaluated in the first consultation at hematology department because of any citopenia or clinical suspicion of any hematologic neoplasm from September 2022 to July 2023. If the patient consented, we recorded it in database and measured blood levels of beta-2 microglobulin on first consultation, and then followed until definitive diagnosis was established. Analysis of data was made with IBM SPSS Statistics for Windows, Version 27.0. Armonk, NY: IBM Corp; we used Mann Whitney U Test for quantitative variable comparison, and Fisher exact test to determine differences between groups. Statistical significances were calculates using p&amp;lt;0.05. Results We captured a total of 87 patients, but 11 had to be excluded because of lack of information. Of the 76 patients included for analysis, 34 were male (44.7%) and 42 were female (55.3%). The medium age was 45.1 years (Range: 15-95 years). After the first consultation, 30 patients (39.5%) were suspected to have a neoplasm, and in follow-up, 35 (46.05%) ended up with a definitive diagnosis of hematologic neoplasm. Only one patient with initial suspected neoplasm ended up with benign disease, but 6 patients in which a bening condition was suspected ended up with a neoplasm diagnosis. There was a total of 35 (46.05%) patients with definitive neoplastic diagnostic, being the most frequent: NHL (n=15, 19.7%), Myeloproliferative neoplasm (MPNs) (n=6, 7.8%), and MM (4, 5.2%). In the no neoplastic pathology, the most frequent diagnosis was iron-deficit anemia (n=17; 22.36%), followed by megaloblastic anemia (n=4, 5.26%) and infectious disease (n=4, 26%). Beta-2 microglobulin was higher in the group with definitive neoplastic diagnosis (5.4mg/L vs 2.4mg/L, x 2=0.053), and was also, significatively higher in the NHL (4.94mg/L, x 2=0.005), MM (13.43mg/L, x 2=0.008), CLL (6.3mg/L, x 2=0.02) and MDS (8.05mg/L, x 2=0.034) subgroups. The sensibility for any hematologic neoplasm was 48.5% and specificity was 82.93%, with a positive LR of 2.84 and a Negative LR of 0.62. The subgroups with higher sensibility were MM (75%), CLL (66.6%), MPNs (66.6%) and MDS (100%), being the Positive LR of 4.3 for MM, 3.9 for CLL, 3.9 for MPNs and 5.86 for MDS. Groups with the lowest correlation were Hodgkin lymphoma (HL) with sensibility of 33.3%, and isolated plasmacytoma (PC) with sensibility of 0%. In the group with benign diagnosis, only 6 (7.89%) presented levels above upper normal limit of blood Beta-2 microglobulin, 4 (5.26%) with iron-deficit anemia, 1 (1.31%) with liver disease, 1 (1.31%) with Pulmonary tuberculosis and 1 (1.31%) with systemic lupus erythematosus; being the highest levels in pulmonary tuberculosis (14.9mg/L). Conclusions The blood levels of beta-2 microglobulin in our work were in concordance with other previous described papers, in which is frequently elevated in NHL, MM, and CCL. But in our case, it showed a marked elevation in MPNs, and MDS (higher correlation). It should be noted, no tumor burden was recorded in our study, which could directly affect beta-2 microglobulin levels. In conclusion, although not a strong correlation as an expert hematologist clinical evaluation, beta-2microglobulin could be of use to strengthen clinical suspicion of those hematologic neoplasms or reassess cases in which MDS/MPNs are a possible differential diagnosis.

Characterization of Cases with the Rare Cytogenetic Abnormality I(7)(p10) Reveals an Association with IDH2 Mutated Acute Myeloid Leukemia

Background: The chromosomal alteration i(7)(p10) is a rare abnormality in hematological malignancies. It leads to a loss of the long arm (7q) and duplication of the short arm (7p) of chromosome 7. However, the presence, frequency and clinical implications of i(7)(p10) in hematological neoplasms has not been analyzed systematically to date. Aim: (1) Analysis of the frequencyand occurrence of i(7)(p10) in hematological malignancies. (2) Characterization of additional cytogenetic alterations and co-occurring mutations. (3) Analysis of potential clinical implications. Patients and methods: All samples sent for diagnosis of suspected hematologic neoplasms between 08/2005 - 05/2023 were used for detection of i(7)(p10). Presence of i(7)(p10) was analyzed using chromosome banding analysis (CBA). In cases with available molecular genetic analyses the following genes were analyzed: ASXL1, BCOR, CEBPA, DNMT3A, EZH2, FLT3-ITD, IDH1, IDH2, KRAS, NPM1, NRAS, RUNX1, SF3B1, SRSF2, STAG2, TET2, TP53, U2AF1 and ZRSR2. Variants of unknown significance were excluded from statistical analysis. All reported p-values are two-sided and were considered significant at p&amp;lt;0.05. Results: In 34 cases an i(7)(p10) was detected. Regarding specific entities, i(7)(p10) was mainly found in AML (23/34, 68%) and rarely in other entities (mature B-cell neoplasms (B-NHL): 6/34, 18%; MDS: 4/34, 12%; ALL: 1/34, 3%). In 20/34 cases, i(7)(p10) comprised the sole cytogenetic abnormality, including 19 AML cases and 1 MDS case. In 10/34 cases, additional chromosomal alterations were detected, leading to a complex karyotype in 5 of these cases. Of note, all cases with a complex karyotype were B-NHL. Additionally, in 4 cases i(7)(p10) was present only in a subclone (1 AML, 1 B-NHL, 2 MDS cases) (Figure A). In 18/34 cases, molecular genetic data was available, revealing DNMT3A (15/18), IDH2 (14/18) and BCOR (7/18) as most frequently mutated genes. As these 18 cases comprised n=15 cases diagnosed as AML, further analysis focused on these patients only. 14/15 cases harbored a mutation in IDH2, the remaining case showed an IDH1 mutation. Further, in 14/15, 7/15 and 4/15 cases, mutations in DNMT3A, BCOR and EZH2 were detected, respectively. By contrast, mutations that are known to frequently co-occur with IDH2 mutations in AML ( SRSF2, ASXL1, NPM1, STAG2, RUNX1, NRAS) were absent or only very rarely detected (Figure B). 12/14 cases with IDH2 mutations showed the mutation site p.Arg172Lys, 2/14 cases p.Arg140Leu, which is known to be the most frequent IDH2 mutation site. This is corroborated by analysis of a control cohort of n=60 IDH2 mutated AML cases without i(7)(p10), in which only 8/60 cases with p.Arg172Lys were detected (86% vs. 13%, p&amp;lt;0.001). Further, comparison of variant allele frequency (VAF) of IDH2 with the VAF of co-mutations suggested the presence of IDH2 in the main clone of all cases, although IDH2 VAF of cases with i(7)(p10) was slightly but not significantly lower than the IDH2 VAF of AML cases without i(7)(p10) (38.3 vs. 45.9). Moreover, comparison of IDH2 mutated AML with and without i(7)(p10) revealed a predominance of females (13/14, 93% vs. 29/60, 48%, p&amp;lt;0.001) and of younger age (63 vs. 72 years, p=0.015) in cases with i(7)(p10). Analysis of overall survival (OS) did not reveal a significant difference between IDH2 mutated AML cases with and without i(7)(p10), although cases with i(7)(p10) showed a trend towards a better outcome (37 vs. 14 months). Conclusions: (1) The rare but recurrent cytogenetic aberration i(7)(p10) is mainly found in AML, where associations with mutations in IDH2, DNMT3A and BCOR were observed. By contrast, other AML-defining mutations ( NPM1, FLT3-ITD, CEPBA) were largely absent, further no defining fusions/rearrangements or a complex karyotype were detected. (2) The vast majority of patients were female and younger than patients with IDH2 mutation without i(7)(p10). (3) Almost all cases showed the rare hotspot p.Arg172Lys and i(7)(p10) as sole aberration, thus it can be speculated that these cases define a distinct subgroup. (4) OS seems to be slightly better than in IDH2 mutated AML without i(7)(p10), although this difference was not statistically significant. (5) Taking into account that the IDH2 mutation was always detected in the main clone and that no other targetable genes/aberrations were observed, these patients are potentially suitable for targeted therapy with IDH inhibitors.

Artificial Intelligence (AI) Based, Machine Learning (ML) Predicting the Individual Absolute Risk of Acute Graft Versus Host Disease (aGvHD) in a Retrospective International Cohort

Background: HSCT still holds potentially lethal complications such as aGvHD, relapse of malignant disease, graft rejection, and infections. 30 to 50% of all patients undergoing HSCT will develop aGvHD, causing high morbidity and mortality (grade 4 GvHD up to 90%) as well as generating significantly higher treatment costs than a HSCT without aGvHD. MatchGraft.AI is an AI based ML algorithm that predicts individual, absolute risk of aGvHD for every individual HSCT donor-recipient pair, based on data available prior to start of conditioning aiming for optimization of donor selection. Methods: MatchGraft.AI has been built in accordance with best clinical practice (Higgins et al 2021). A random forest is used to predict the probability of aGvHD free survival, GvHD free death and aGvHD. Missing data are imputed, except for the gradient boosted tree, by using the most frequent category for categorical variables and mean value for continuous variables. The performance characteristics are calculated in an aGvHD vs Rest (death or aGvHD free survival) fashion. The data is split into a stratified training and validation set with a ratio of 80% / 20%. Results: The model was trained at Charité University against a retrospective, multi center data set of 1035 German and north American patient/donor sets. We collected 1719 data sets. 684 cases were excluded due to mayor outcome parameters not being available. The following analyzation focuses on the 1035 included stem cell transplantation patient/donor sets (828 training set/ 207 validation set), 356 pediatric patients, 679 adults. M:F = 1,5; age 0 - 76 (median: 39.5 +/- 24.3 years). Indications for transplantation were malignant diseases (hematological neoplasms, lymphomas, solid tumors) in 731 patients and benign diseases (hemoglobinopathies, immune deficiencies, bone marrow failure) in 205 cases, in 99 cases diagnosis was not documented. Transplantations were performed between January 2013 and December 2019. Despite some missing data in our retrospective cohort, model performance was estimated at 0.70 AUC (fig.1). Integrated calibration index was 0,0277. Discussion: MatchGraft.AI predicts the risk of acute GvHD. By providing precise prediction of relevant complications, we expect the pool of possible donors to become larger as well as donor selection to improve. Furthermore, physicians and patients will be able to better prepare and adapt conditioning and treatment plans with MatchGraft.AI predictions. Conclusions: The prediction of individual aGvHD risk, using this AI ML model, is feasible and well calibrated, especially in the medium risk area. Ongoing continuous training, testing and adapting on additional international, multicenter retrospective and prospective data will further improve performance in the low risk area. This study is the basis for further prospective research.

LSD1 Inhibition Synergizes with Venetoclax in Acute Myeloid Leukemia By Targeting Cellular Metabolism

Introduction: Acute myeloid leukemia (AML) is a hematological neoplasm with poor clinical outcomes. The introduction of the BCL2 inhibitor venetoclax in combination with hypomethylating agent has improved response rates in older patients with AML by targeting the metabolism of leukemic stem cells (LSCs). Resistance, however, is unfortunately still common. Thus, there remains a need to enhance the clinical efficacy of venetoclax by combining it with novel agents. In diverse AML models, lysine-specific demethylase 1 (LSD1) inhibition promotes cellular differentiation and reduces LSCs. We therefore asked if LSD1 inhibition could enhance the efficacy of venetoclax in the treatment of AML. Methods: We have studied the effect of single-agent and co-treatment with venetoclax and LSD1 inhibitor bomedemstat on cell proliferation in human AML cell lines (N=3), Hoxa9/ Meis1(H9M)- and MN1-transformed murine myeloid progenitor lines as well as primary AML patient samples (N=5). We have analyzed the effect of co-treatment with these two compounds on functional cellular bioenergetics in MOLM-13 cells using Seahorse extracellular flux analyzer and followed up by performing NMR spectrometry to study changes in metabolite abundance. Further, we have studied the efficacy of this drug combination in vivo in patient-derived xenograft (PDX) AML models (N=2). Results: Human AML cell lines showed a differential cytocidal activity at 96 hours (h) to venetoclax with MOLM-13 (IC 50 0.04 µM) being most sensitive and OCI-AML3 most resistant (IC 50 9.81 µM). A similar range (between 0.15 µM and 7.3 µM) was also observed in the primary AML samples. For bomedemstat, we observed a time-dependent response where the IC 50 decreased over time, in particular, in the most sensitive model systems. In murine H9M cells, the IC 50 decreased from 30.43 µM at 48 h to 0.034 µM at 96 h and further down to 0.0068 µM at 168 h. Combining bomedemstat and venetoclax, the IC 50 for venetoclax decreased; and synergism was observed in MOLM-13 cells, the most sensitive AML model, but no synergism was observed in venetoclax-resistant cells. Synergism was also observed in MN1 cells as well as 3 of the 5 primary AML samples studied (Table 1). To investigate the mechanism of the observed synergism, we explored the effect of these treatments on metabolic pathways using the Seahorse extracellular flux analyzer. LSD1 inhibition had no effect on oxidative phosphorylation (measured as oxygen consumption rate (OCR)). However, glycolysis, measured as proton efflux rate (PER), was significantly reduced from 102.88 ± 11.03 pmol/min to 54.17 ± 6.18 pmol/min (P &amp;lt;0.01) after 96 h of treatment with 1μM bomedemstat. With the combined treatments, we observed a reduction in both OCR and PER. This synergistic effect was further investigated by studying metabolite abundance using NMR spectrometry where co-treatment showed a reduction in metabolite abundance across a broad spectrum of metabolic pathways (Fig. 1). To determine if the observed combined effect of bomedemstat and venetoclax could enhance activity against AML cells in vivo, we employed a PDX model with two primary AML samples. In the first model system (monosomy 7), co-treatment resulted in a significant reduction in human CD45-positive cells as compared to vehicle (P &amp;lt;0.001) and single-agent treatments with venetoclax (P= 0.011) and bomedemstat (P &amp;lt;0.001). Similarly, in the second PDX model ( NPM1-mutated, FLT3-ITD positive), the co-treatment exhibited a significant reduction in leukemic burden in bone marrow as compared to vehicle (P=0.003) and single-agent treatments with venetoclax (P= 0.024) and bomedemstat (P &amp;lt; 0.001) (Fig. 1). Conclusion: The combination of bomedemstat and venetoclax had synergistic cytocidal effects on AML cell line and primary AML cells in vitro. It significantly reduced the leukemic burden in PDX AML models and synergistically downregulated cellular energy metabolism. These findings suggest that combining venetoclax with LSD1 inhibition holds promise as a combination treatment in AML and warrants further clinical investigation.

Investigating the Influence of Germline ATM Variants on Susceptibility to Chronic Lymphocytic Leukemia and Other Malignancies

Introduction: Chronic lymphocytic leukemia (CLL) patients (pts) face an increased susceptibility to secondary cancers. Furthermore, the hereditary predisposition to CLL is influenced by factors that have yet to be fully elucidated by GWAS-identified common variants. Among the hereditary cancer risk mutations observed, germline Ataxia-telangiectasia mutated ( ATM) aberrations are among the most prevalent. Rare germline ATM variants are detected in 24% of CLL pts, surpassing the frequency observed in other hematologic neoplasms and the general population. In CLL, loss of ATM via 11q23 deletion is linked to an unfavorable prognosis and a shortened progression-free survival. The extent to which germline ATM variants predispose CLL pts to other malignancies remains unclear; to examine this potential risk we conducted a retrospective study to assess the influence of germline ATM variants on the predisposition to secondary neoplasms in CLL pts and their relatives. Methods: Five hundred and eighty-five pts seen at Dana-Farber Cancer Institute and who had NGS performed to evaluate germline ATM status, either through direct germline sequencing of saliva or by inference according to the hierarchical algorithm we have previously published (Lampson, 2022), were mailed a questionnaire that investigated: demographics; personal and family history of any cancer; non-medical radiation and Agent Orange exposure; and Ataxia-Telangiectasia syndrome (AT). Of these, 333 replied (57%). Information collected from our CLL database included FISH, IGHV status and treatment status. European ancestry was categorized based on the United Nations geoscheme (UNSD, 2019). Pt characteristics are in Table 1. Pts were stratified into 4 groups, based on ATM mutational status and del(11q): Group-1, ATM germline variants alone (N=63); Group-2, ATM germline with somatic ATM mutation and/or del(11q)(N=22); Group-3, ATM somatic aberration alone (including del(11q))(N=41); and Group-4, no ATM aberration (N=207). Results: Of the 333 pts in our cohort, baseline demographic and clinical characteristics among the 4 groups were balanced, except for unmutated IGHV status. Nineteen (86%) and 36 (86%) pts of groups 2 and 3, carrying somatic ATM aberrations, had unmutated IGHV, compared to 21 (33%) and 76 (37%) of groups 1 and 4, without somatic ATM aberrations(p&amp;lt;0.01). Regarding treatment, 60% of our cohort had received at least one line of therapy (median: 1 (1-7)). Among the 164 pts (49%) with history of an additional non-CLL neoplasm, 221 cancers were reported. Excluding pts with only non-melanoma skin cancers, the incidence is reduced to 31% (104 pts). The median number of second cancers per pt is 1 (1-4). Of the 134 pts with available age of onset data for the secondary malignancy, 80 (60%) were diagnosed with the secondary cancer after CLL. Comparing pts with germline ATM variants (N=85) to the ones without germline ATM variants (N=248), no significant difference in the incidence of secondary cancer was found (p=0.73). The median age of secondary cancer onset was also similar between the groups (median: 63 and 64 years in germline ATM present vs absent, p=0.28). Of the whole cohort, 283 pts (85%) reported at least one relative with a cancer history (median 2 relatives affected (1-17)). The incidence of B-cell lymphoproliferative disorders was significantly higher (p=0.02) in pts with germline ATM variants (32%) compared to those without germline ATM variants (21%), including familial CLL (25% vs18%) (p=0.04). Familial CLL was also strongly associated with Ashkenazi Jewish ethnicity (39% incidence in Ashkenazi pts vs 16% in non-Ashkenazi, p=0.004). No difference in the incidence of other hematologic or solid malignancies was found between the relatives in the two groups. No pts reported a familial or personal history of AT. Compared to pts without any ATM aberration, time to first treatment (TTFT) was shorter in pts harboring somatic ATM events, while no difference was observed between pts with germline ATM variants (median TTFT: 82, 59, 52, 90 months for group 1, 2, 3 and 4 respectively, p=0.01) (Figure 1). Conclusions: Our results suggest a higher incidence of B-cell lymphoproliferative disorders, including familial CLL, in the relatives of CLL pts carrying germline ATM variants. The presence of these germline variants did not impact TTFT, compared to pts harboring somatic ATM mutations.

Incidence and Prevalence of Mastocytosis in Adults: A Danish Nationwide Register Study

Introduction: Mastocytosis is a heterogeneous chronic disease caused by a mutation in the cKIT gene that allows for uncontrolled proliferation, accumulation and activation of abnormal mast cells. Mastocytosis is divided into cutaneous mastocytosis (CM) and systemic mastocytosis (SM) in which abnormal mast cells are found in various tissues of the body. SM is further divided into the following five subtypes related to disease severity: indolent systemic mastocytosis (ISM), smoldering systemic mastocytosis (SSM), aggressive systemic mastocytosis (ASM), systemic mastocytosis with an associated hematologic neoplasm (SM-AHN) and mast cell leukemia (MCL). Mastocytosis is considered a rare disease with an incidence and prevalence previously found to be 0,89 per 100.000 and 9,59 per 100.000, respectively; however, recent improvements related to diagnostic methods could have led to an increased incidence and prevalence. Therefore, updated data is needed. Methods: This study is a retrospective nationwide register study including all adult (≥18 years) patients with mastocytosis in Denmark diagnosed between January 1 st 1997 and December 31 st 2021. The study was conducted using the Danish Civil Registration System to merge data from the National Patient Register (NPR), the Danish Pathology Register (DPR) and the Danish Cancer Register (DCR). The National Patient Register contain information on all inpatient and outpatient contacts and is considered complete as of 1995-2018. The Danish Pathology Register contain information about all biopsies and pathologic examinations in Denmark and is considered complete as of 1997 to 2021. The Danish Cancer Register contain information on all incidences of cancer in Denmark and is considered complete as of 1987-2021. Year of diagnosis was considered as the earliest date across all registers and patients were categorized as most severe subtype of mastocytosis. The registers did not allow for a categorization of SSM and therefore indolent mastocytosis were all categorized as ISM. Patients without a positive extracutaneous biopsy and who have never been examined with a bone marrow biopsy were classified as mastocytosis in the skin (MIS). Results: These data are the preliminary results of this study. 1627 patient were included (female 924, 56,8%). Mastocytosis in the skin was the most prevalent type of mastocytosis (774, 47,57%), followed by ISM (441, 27,11%), CM (222, 13,64%) and SM-AHN (179, 11%), More than 80% of patients with ASM had another hematologic neoplasm and were categorized as SM-AHN. Few patients were classified as ASM (4, 0,25%) and MCL (7, 0,43%). A positive bone marrow biopsy was found among 601 (36,94%) of the patients; however, 774 (47,57%) patients with mastocytosis were not examined with a bone marrow biopsy. The incidence rate of mastocytosis (all subtypes) was lowest in 2003 with an incidence of 0,74 per 100.000. Hereafter, the incidence increased until reaching the highest level in 2018 with an incidence of 2,77 per 100.000 (figure 1). The 25-year limited-duration prevalence as of 1 st January 2022 was 28,44 per 100.000. Conclusion: This nationwide register study provides updated data on the prevalence and incidence of mastocytosis in Denmark. The incidence rate was found to have an increasing trend until 2018 when it reached the highest value of 2,77 per 100.000. The prevalence was found to be 28,44 and thereby higher than previous studies have found. However, the true prevalence is potentially higher as the data for the years 2019-2021 solely relies on the pathology register. This is preliminary data, and the results will be updated when the NPR is complete for these years.Further analysis will be conducted using the Register of Laboratory Results for Research to evaluate blood tests regarding tryptase levels as well as to provide further information regarding KIT mutational status.

Organ Involvement in BPDCN Is Associated with Sun Exposure History, TET2 and RAS Mutations, and Survival

Introduction Blastic plasmacytoid dendritic cell neoplasm (BPDCN) is a rare, aggressive hematologic neoplasm that can involve skin, bone marrow (BM), central nervous system (CNS), and non-CNS extramedullary disease (EMD) sites. Recent findings show that ultraviolet light (UV) exposure may contribute to the development of BPDCN (Griffin, Nature 2023). Conflicting data exist as to whether anatomic involvement is clinically relevant, and genetics have not been incorporated into disease site prognostic models. In addition, the role of non-overt (&amp;lt;5%, microscopic) BM involvement remains unclear as trials have only regarded ≥5% as evidence of BPDCN. Methods We assessed associations between organ involvement, UV exposure, molecular characteristics, and outcome in patients with biopsy-confirmed BPDCN seen at Dana-Farber Cancer Institute between 2006-2022. UV exposure was classified as high vs. low by an independent reviewer blinded to outcomes, based on medical, social, and occupational history. We classified 3 groups at diagnosis: systemic without skin (either BM with ≥5% BPDCN cells or EMD and no skin involvement), skin only (with no overt BM [&amp;lt;5% BPDCN cells] and no EMD), or skin and systemic; groups were classified irrespective of CNS involvement at diagnosis. Next generation sequencing was performed on blood/BM at diagnosis. Comparisons were performed by Fisher's exact test. Survival was calculated from treatment initiation and comparisons made by the log-rank test. Uni- and multivariable Cox regression models were fit for association with overall survival (OS), with SCT as a time varying covariate. Results Overall, we included 66 consecutive patients with a median age at diagnosis of 68 years (interquartile range [IQR] 61-76). The majority (n= 57, 86%) of patients were male. Disease distribution at diagnosis involved skin (n=52, 79%), BM (n=50, 76% [39 (59%) with ≥5% BPDCN cells]) and EMD (n=30, 45%), ( Table, Figure). The median time from first symptom to diagnosis was 61 days (IQR 35-134) and from diagnosis to treatment was 30 days (IQR 20-46). The first therapeutic regimen was tagraxofusp (n=30, 45%), AML (n=12, 18%) or ALL (n=12, 18%) chemotherapy, or other treatment (n=12, 18%). Complete remission (CR) after first treatment was documented in 35 (57%) with 20/35 consolidated in CR1 with SCT (57%); however, after a median of 6.1 months from response assessment (IQR 2.4-8.1 months), 22/35 who achieved CR relapsed, with skin (n=13, 54%), BM (n=12, 50%), EMD (n=5, 21%), or CNS (n=3, 13%) as relapse sites. The median number of therapies was 2 (0-6), and 35 (53%) had SCT at any time. The pattern of post-SCT relapse included disease involvement in skin (8/14, 57%), BM (5/14, 36%), EMD (3/14, 21%) and CNS (3/14, 21%). Patients with skin only at diagnosis (n=19) vs. any systemic involvement (n=47) were more frequently ≥75 years (9/19 [47%] vs. 9/47 [9%], p=0.032), had lower rates of complex karyotype (0 vs. 12 [32%], p=0.022) and activated signaling mutations ( N/KRAS, FLT3, CBL, CKIT, S H2B3; 1 [8%] vs. 14 [40%], p=0.04), mainly driven by lower NRAS (0 in skin only vs. 10 [29%] with any systemic, p=0.044, Figure). In contrast, those with any skin involvement had higher rates of UV exposure (27 [59%] vs. 3 [23%], p=0.03) and TET2 mutations (28 [72%] vs. 3 [33% ], p=0.051) compared to those with no skin involvement, consistent with the recently aforementioned link between UV exposure and selection for TET2 mutated plasmacytoid dendritic cells. The median OS of the entire group was 18.2 months (95% CI 13-24) and did not statistically differ between presentation groups (skin only: 23.5 [95% CI 13-NR]; systemic + skin 20.4 [95% CI 11-26]; systemic only 17.5 [95% CI 9-22], p=0.14). In a multivariable analysis, age &amp;lt;60 (HR 0.35 [95% CI 0.13-0.94], p=0.038) was associated with improved OS, whereas BM involvement ≥5% (but not microscopic involvement) was independently associated with worse OS (HR 2.65 [95% CI 1.1-6.36]). Conclusions Specific organ involvement in BPDCN is associated with UV exposure, age, cytogenetic and molecular characteristics. Skin is the most common relapse site post CR or SCT. Survival is better in younger patients (age &amp;lt;60 years), and worse in those with ≥5% BM involvement after adjustment for age and SCT. These data establish additional factors that, in combination, have prognostic value in BPDCN, and provide independent evidence that sun exposure influences BPDCN genetics and clinical presentation.

Deep and Durable Cytogenetic and Molecular Responses with Pemigatinib in Myeloid/Lymphoid Neoplasms with Fibroblast Growth Factor Receptor 1 Rearrangement: The Fight-203 Study

Introduction:Myeloid/lymphoid neoplasmswith fibroblast growth factor receptor 1 rearrangement (MLN FGFR1) are aggressive hematologic neoplasms caused by various reciprocal translocations involving chromosome band 8p11, resulting in tyrosine kinase fusion genes (eg, ZMYM2::FGFR1 from t[8;13][p11;q12] or BCR::FGFR1 from t[8;22][p11;q11]) and constitutive FGFR1 activationand downstream signaling. Pemigatinib is a potent and selective oral inhibitor of FGFR1-3 approved for the treatment of adults with relapsed or refractory MLN FGFR1. Efficacy and safety data for 41 patients with MLN FGFR1 in the ongoing FIGHT-203 study of pemigatinib were previously reported. Median daily pemigatinib dose was 9.5 mg; treatment-emergent adverse events led to dose interruptions in 66% of patients. Rates of complete response (CR) among the 38 patients evaluable for clinical response and rates of complete cytogenetic response (CCyR) for the 40 patients evaluable for cytogenetic response were 74% and 70%, respectively. CR and CCyR occurred in &amp;gt;80% of patients with chronic phase disease and in &amp;gt;50% of patients with blast phase disease. Here we present an analysis of centralized fluorescence in situ hybridization (FISH) evaluation of bone marrow (BM) cells and serial characterization of levels of FGFR1 fusion transcripts in this same cohort. Methods: FIGHT-203 (NCT03011372) is an ongoing open-label, multicenter, phase 2 study evaluating pemigatinib in patients ≥18 years old with MLN FGFR1 and ≥1 prior therapy. The starting dose was pemigatinib 13.5 mg daily (2 weeks on, 1 week off). Following protocol amendments, patients without prior therapy were eligible to enroll, and the dosing regimen was changed to a continuous schedule. Patients were censored for cytogenetic and molecular follow-up at the time of transplantation. CCyR was defined as 0 metaphases positive for the respective reciprocal translocation in ≥20 evaluated BM metaphases on local and/or central karyotyping or 0 cells (or not exceeding the lower level of detection of the probe) with the FGFR1 rearrangement in ≥200 BM cells on local and/or central break-apart FISH assays (central FISH prioritized). As part of the translational research plan, fusion partner genes were identified with next-generation sequencing (NGS; FusionPlex, Archer, Boulder, CO, USA) and targeted PCR profiling of RNA extracted from whole blood; droplet digital PCR (ddPCR) assays were developed to monitor the frequencies of specific FGFR1 fusion transcripts in RNA extracted from whole blood samples (estimated limit of detection, 0.05 copies/μL). Results: As of June 30, 2021, 39 of 41 enrolled and treated patients were evaluable for translational analyses. Among the 39 patients with whole blood samples, FGFR1 fusion partner genes identified on translational testing were ZMYM2 (n=17), BCR (n=11), FGFR1OP (n=4), TPR (n=3), TRIM24 (n=2), and C14orf93, CCDC6, CNTRL and ETV6 (n=1 each). Two of 39 patients had 2 fusions detected ( ZMYM2 and BCR, n=1; ZMYM2 and TPR, n=1). C14orf93, CCDC6 and ETV6 have not been previously identified as FGFR1 fusion partner genes. Central FISH assessment of BM cells confirmed FGFR1-aberrantcells were reduced to undetectable levels in responding patients but rebounded in some patients during periods of treatment interruption (Figure A). Serial ddPCR of whole blood samples demonstrated marked reductions in FGFR1 fusion transcripts for the 34 patients with ≥3 measures while on treatment (Figure B). Among patients with CR, 81.0% had a &amp;gt;2-log reduction and 47.6% had a &amp;gt;3-log reduction in detectable FGFR1 fusion transcripts. Smaller reductions in FGFR1 fusion transcripts were observed in patients with stable disease. Changes in FGFR1 fusion transcripts correlated with FGFR1 FISH results (Pearson coefficient = 0.81) and reflected changes in treatment intensity. Conclusion:Several new FGFR1 fusion partner genes, including C14orf93, CCDC6, and ETV6 were identified with NGS and PCR profiling. Pemigatinib treatment resulted in marked decreases in the percentages of cells with the FGFR1 rearrangement on FISH, as well as 2-3 log reductions in FGFR1 fusion transcripts in patients with MLN FGFR1. Further investigations are ongoing to determine the relationship between pemigatinib dose intensity and the depth and durability of molecular response.

Hidac Consolidation Cycles May Impede Stem Cell Transplant Planning for High-Risk Acute Myeloid Leukemia Patients

Background Acute myeloid leukemia (AML) is a clonal aggressive hematologic neoplasm characterized by arrested myeloid maturation, resulting in the accumulation of myeloid blasts in bone marrow, blood, and other tissues. Cytogenetic and molecular characteristics further stratify AML into favorable, intermediate, or high-risk classifications; with high-risk including DEK-NUP214, KMT2A-rearrangement, BCR-ABL1, GATA2, MECOM, deletion 5q, abnormal 17p, complex or monosomal karyotype, wild type NPM1 and FLT3-ITD, or mutated: RUNX1, ASXL1, or TP53. In fit and eligible patients, therapy for high-risk AML patients involves induction therapy, and response evaluation at count recovery. If remission is confirmed, it is ideal that the patient proceed straight to hematopoietic stem cell transplantation (HSCT). HSCT remains the only curative therapy currently available. The logistics of proceeding to transplant might necessitate consolidation chemotherapy usually involving high dose cytarabine (HiDAC). Methods We performed a retrospective cohort analysis and evaluated outcomes for high-risk AML patients treated at our transplant institution, the Georgia Cancer Center, who were diagnosed and received HiDAC consolidation therapy between November 2003 and December 2020. High-risk AML was defined as those patients, whose AML was positive for one (or more) of the following FLT3, monosomy 5,7 and/or complex cytogenetics (CG) defined as having greater than or equal to 3 CG changes). For those not transplanted, we reviewed the complications, if any, that would preclude a HSCT. Results A total of 93 patients diagnosed with high-risk AML were evaluated at our center from 2003 to 2020. Males comprised 46.2% (n=43) and females comprised 53.8% (n=50) of the cohort. Of these patients, the median age of the patient cohort was 61.5 years. 40.8% (n=38) received HiDAC consolidation. Among patients who received HiDAC consolidation and proceeded to undergo HSCT, the median age was 47.6 years. In contrast, patients who received HiDAC consolidation but were unable to undergo HSCT had a median age of 61.3 years. Among the patients who were unable to undergo HSCT due to death, the median age was 41.8 years. For patients who received HiDAC consolidation but did not undergo HSCT due to reasons other than death, the median age was 53.4 years. 55.3% (n=21) went on to HSCT, and others did not proceed to HSCT. Of the patients who did not receive HSCT, 76.4% (n=13), underwent HLA-typing, indicating consideration for transplantation. Of these 17 patients (44.7%, n=9) did not proceed to transplant due to infectious complications, the remaining 8 had noninfectious reasons for non-transplant. Of the 9 patients without HSCT due to infection, four had an infection that prevented them from receiving a transplant and five patients passed away prior to transplant due to septic shock or multi-organ failure. Infections included bacteremia from Klebsiella, E. Coli, Proteus, group B strep, vancomycin resistant E. Faecalis, and coagulase negative staph, pneumonia from Klebsiella, urinary tract infections from extended spectrum beta-lactamase resistant E. Coli, Klebsiella, and proteus mirabilis, fungal sinusitis, and Clostridium difficile colitis. Other reasons that prevented HSCT included neutropenic fever with an unknown cause, substance abuse, disease progression, and lack of follow-up. Conclusion The data from our study and the literature on this topic over the past 30 years suggest starting the process of HSCT during the induction admission. HSCT is the sole curative option for high-risk AML patients, and the concept of bridging the period between induction and HSCT with HiDAC consolidation appears to offer no additional benefit compared to IDAC. Moreover, this approach prevents a subset of this population from being fit enough to receive HSCT.

Decreased Survival Among Patients with Indolent Systemic Mastocytosis: A Population-Level Retrospective Cohort Analysis Using Healthcare Claims Dataset

Background Systemic mastocytosis (SM) is a rare, clonal mast cell disease driven by the KIT D816Vmutation in ~95% of cases and can be subdivided into two predominant subtypes - advanced SM (AdvSM) and indolent SM (ISM). AdvSM comprises ~15% of all patients and is characterized by mast cell proliferation and infiltration causing subsequent dysfunction of various organ systems, leading to reduced overall survival. Indolent systemic mastocytosis (ISM) comprises the bulk of the remaining ~85% of patients and is characterized by a less severe clinical course that is nevertheless associated with a significant symptom burden that may worsen over time, poor quality of life, and the potential for life-threatening anaphylaxis. Recent epidemiologic data indicate ISM is a heterogenous disease. A meaningful subset of patients with disease risk factors demonstrates high symptom burden, which may be associated with higher rates of disease progression and increased risk of death (Sperr, et al. Lancet Hematol. 2019). Building upon this work, we conducted an analysis to evaluate overall survival (OS) in ISM patients. Methods Using a nationally representative health claims dataset provided by Komodo Health covering 230 million US patients (2015 to 2022), we identified 8,332 patients with ISM using a claims-based algorithm. This algorithm leverages combinations of ICD-10 dx codes for SM and organ dysfunction, procedure codes (bone marrow biopsy), and use of SM-directed therapies (Mukherjee et al ASH 2022). Patients were included if full medical and pharmacy claim information was available for &amp;gt;12 consecutive months post-diagnosis, and median follow-up was 4.0 years. ISM was inferred as a dx if only the broad systemic mastocytosis ICD-10 code was used (D47.02) and there was no preceding evidence of AdvSM or an associated hematologic neoplasm. Disease progression to AdvSM was inferred if there was subsequent evidence of mast cell leukemia, aggressive SM, or an associated hematologic neoplasm OS was then calculated, anchored to the first observed ICD-10 dx code for SM. Mortality information was available within the claims dataset and was additionally inferred if a patient did not generate any medical or pharmacy claims for 12 or more consecutive months. Three, independent non-SM control cohorts (N=2000 each) were established for comparison, based on a stratified sampling strategy matched by gender, age, Charlson Comorbidity Index, payer status, and race/ethnicity of the ISM population. Multiple cohorts were plotted to illustrate consistency in survival across independently-sampled control cohorts. As positive control, we compared OS with a cohort of patients with ASM, a disease cohort with known increased mortality. Results We observed a statistically significant difference in OS among patients with ISM versus the matched non-SM control cohorts ( p&amp;lt;0.0001, with a log-rank hazard ratio of 1.64; Figure 1A). Excess mortality was noted among ISM patients with or without evidence of disease progression ( p&amp;lt;0.0001, with a hazard ratio of 1.44) compared to matched non-SM cohorts ( Figure 1B). As expected, OS was worst in patients with AdvSM ( p&amp;lt;0.0001, with a hazard ratio of 6.64). The ISM cohort presented to the emergency room (ER) 0.70 times per year, compared to 0.31 times per year for the combined non-ISM control cohorts, based on the sum of ER visits observed across the cumulative cohort observation period. Patients with ISM who died during the study interval had the highest frequency of ER visits, at a rate of 1.09 visits per year. Conclusions This is the first and the largest population-level analysis of OS in the ISM population in the US. Results demonstrate a modest but statistically significant decrease in survival among these patients even early in their disease course (first 4 years). This increase in mortality was observed even among patients with no evidence of progression to advanced SM and was additionally associated with &amp;gt;2x higher rates of ER visits over the observation period. These results suggest that acute, severe symptoms of SM may contribute to the excess mortality seen among patients with ISM and warrant focused research to identify specific patient characteristics or disease features in ISM that confer higher risk of mortality.