Search

FLT3 mutations are present in 30% of newly diagnosed patients with acute myeloid leukemia. Two broad categories of FLT3 mutations are ITD and TKD, with the former having substantial clinical significance. Patients with FLT3-ITD mutation present with a higher disease burden and have inferior overall survival, due to high relapse rates after achieving remission. The development of targeted therapies with FLT3 inhibitors over the past decade has substantially improved clinical outcomes. Currently, two FLT3 inhibitors are approved for use in patients with acute myeloid leukemia: midostaurin in the frontline setting, in combination with intensive chemotherapy; and gilteritinib as monotherapy in the relapsed refractory setting. The addition of FLT3 inhibitors to hypomethylating agents and venetoclax offers superior responses in several completed and ongoing studies, with encouraging preliminary data. However, responses to FLT3 inhibitors are of limited duration due to the emergence of resistance. A protective environment within the bone marrow makes eradication of FLT3mut leukemic cells difficult, while prior exposure to FLT3 inhibitors leads to the development of alternative FLT3 mutations as well as activating mutations in downstream signaling, promoting resistance to currently available therapies. Multiple novel therapeutic strategies are under investigation, including BCL-2, menin, and MERTK inhibitors, as well as FLT3-directed BiTEs and CAR-T therapy.

Background Patients with myeloproliferative neoplasms (MPNs), such as polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF), are at an increased risk of recurrent thromboembolic events (TEs) and hemorrhagic complications. Anticoagulation with vitamin K antagonists (VKAs) had been the standard of care until the recent US Food and Drug Administration approval of direct oral anticoagulants (DOACs) for treatment of cancer‐associated thrombosis. However, since patients with MPNs were underrepresented in large studies, the use of DOACs in patients with MPN‐associated thrombosis remains understudied. Objectives The primary objective of this study was to establish the incidence of recurrent TEs and hemorrhagic complications in patients with MPN‐associated thrombosis treated with DOACs versus VKAs as first‐line therapy. Methods Data from 30 patients ≥18 years old with established diagnoses of PV or ET who were treated with either DOACs or VKAs as the first‐line anticoagulant for arterial and/or venous thrombosis were reviewed to determine the incidence of recurrent TEs as well as hemorrhagic complications. Results Nineteen patients were treated with DOACs, and 11 were treated with VKAs. Of those on DOACs, 1 had a recurrent thrombosis, and 4 had bleeding events. Of the 11 patients treated with VKAs, 1 had a recurrent thrombotic event, and 1 had a bleeding event. Conclusion Our data did not demonstrate a significant difference in recurrent TEs or bleeding events in patients with MPN‐associated thrombosis anticoagulated with either DOACs or VKAs.

Background: Autologous hematopoietic stem cell transplant (auto-HSCT) is a commonly used treatment for multiple myeloma (MM) and for relapsed/refractory non-Hodgkin lymphomas (NHL) for patients who are 65 years old, and nearly half of those are in patients >75 years old. While some studies have evaluated the use of auto-HSCT in older patients 65-75 years of age, there are few studies evaluating the relative safety of this treatment in patients above the age of 75 years. Such patients and their providers require outcome data of auto-HSCT in the elderly in order to help guide informed decision-making. Methods: We conducted a retrospective cohort study comparing short-term outcomes for auto-HSCT in patients >75 years old and 55-65 years old for the diagnosis of MM or NHL, who were conditioned with either melphalan or BEAM (carmustine, etoposide, cytarabine, melphalan) respectively. To identify patients, we used an internal database of auto-HSCT performed between 2005 - 2021. The study group included patients >75 years old. The control group included patients 55-65 years old that were matched to the study group patients by sex and time of transplant. Medical records were reviewed to gather data on demographics, pre-transplant functional status, transplant indication and conditioning regimen, length of stay, admission mortality, 30-day rehospitalization rate, ICU admission, neutropenic fever and infectious workup results, and time to WBC and platelet engraftment. The primary outcomes of the study were admission mortality, length of stay, time to WBC and platelet engraftment incidence, incidence of neutropenic fever, positive blood culture, ICU admission, and 30-day rehospitalization rate. Averages were calculated using medians and IQR. Admission mortality was evaluated using log rank test. P values were calculated using Fisher's test for categorical data and Wilcoxon rank sum test for continuous data. Significance was denoted by α =0.05. Results: We identified 43 patients aged >75 years old who underwent autologous stem cell transplant for multiple myeloma or lymphoma with melphalan or BEAM conditioning at Montefiore Medical Center between 2005-2021. Patient characteristics (Table 1) The earliest transplant in out cohort was in 12/2005 and the latest was in 3/2021. The median time between transplants of patients in the study and cohort groups was 14 [7.5, 24] days. 24 (55.8%) patients were female. The median age in the study group was 77.1 [76.2, 77.9] years old and 61.9 [57.4, 63.0] years old in the control group. Both groups predominantly included patients from minority populations: 55.8 and 46.5% were Spanish/Hispanic/Latino and 25.6% and 14.0% were African American, in study and control groups respectively. Multiple myeloma was the most common indication for auto-HSCT. Primary outcomes (Table 2) Admission mortality did not differ significantly between the groups, with only one death in the control group (p = 0.083). The length of stay was comparable at 18 [17, 22] days and 19 [16, 20] days (p = 0.2) for study and control groups, respectively. Time to WBC engraftment in the study group was 12 [11, 12] days and 11 [11, 12] days in the control group (p = 0.032). Time to platelet engraftment in the study group was 14 [12, 15] days and 12 [11, 14] days in the control group (p = 0.014). Although both time to WBC and platelet engraftment was significantly longer in the study group, the clinical significance of this finding is questionable, especially as it did not seem to prolong length of stay. There was no significant difference between incidence of neutropenic fever, or between incidence of positive blood cultures in patients with neutropenic fever. There was a non-statistically significant increase in the rate of ICU admissions in the study group vs control group 4/43 and 0/43 respectively (p=0.12). 30-day rehospitalization rate was comparable between the two groups. Conclusion: We did not find a statistically significant increase in morbidity or mortality for patients 75-80 years of age undergoing auto-HSCT compared with patients 55-65 years old. To our knowledge this is the largest cohort to date demonstrating the safety of auto-HSCT in this elderly population. Figure 1 Figure 1. Disclosures Gritsman: iOnctura: Research Funding. Shastri: Onclive: Honoraria; GLC: Consultancy; Kymera Therapeutics: Research Funding; Guidepoint: Consultancy. Verma: Medpacto: Research Funding; Curis: Research Funding; Eli Lilly: Research Funding; Stelexis: Consultancy, Current equity holder in publicly-traded company; Novartis: Consultancy; Acceleron: Consultancy; Celgene: Consultancy; Stelexis: Current equity holder in publicly-traded company; Throws Exception: Current equity holder in publicly-traded company; Incyte: Research Funding; GSK: Research Funding; BMS: Research Funding.

Background Digitized microscopy such as CellaVision® technology has revolutionized the laboratory. Smudge cells, also called basket cells, are usually seen in lymphoproliferative disorders representing remnants from degenerated lymphocytes (DLs). CellaVision® classifies DLs and web-like remnants as smudge cells. The morphology of the web-like remnants is compatible with Neutrophil Extracellular Traps (NETs) where extracellular decondensed DNA chromatin network is formed as one of several neutrophilic reactions to stress. Currently, we lack clinical tests that reliably identify and quantify NETs. Aims To develop an in-vitro model for NETs formation in blood, create a library of their morphological changes at different maturation stages; correlate their presence to infections in absence of leukocytosis and develop an artificial intelligence platform (AI-Heme-1) for their detection. Methods A library was built to develop AI-Heme-1 where NETs were induced with classic triggers (phorbol-myristate-acetate, lipopolysaccharide and ionomycin) in EDTA whole blood from normal subjects. Smears were prepared at 30 minutes intervals for 24 hours to identify NETs by Immunofluorescence and immunohistochemistry. WBC differentials were performed by CellaVision® to capture different stages of NETs. AI-Heme-1 was modified from Python online convolutional neural network. For the clinical correlation, smears with >20% smudge cells were classified morphologically as NETs vs. DLs compared to a control group, < 5% smudge cells. We used morphologic characteristics, immunohistochemistry, immunofluorescence and flow cytometry to differentiate NETs from DLs. Medical chart review performed by blinded investigators, included patient demographics, CBC and presence of microbial infection occurring < 1 week of sample collection. Statistical analyses included two sided t-test and chi square. Results The classical triggers for Netosis showed consistent morphological changes following a canonical order: vacuolation, nuclear decondensation, degranulation and chromatin ejection. These cell remnants were positive for citrullinated histones, myeloperoxidase, leukocyte alkaline phosphatase and neutrophil elastase by immunofluorescence. On Wright Giemsa stain, web-like remnants resembling NETs stained for SytoxGreen. On flow cytometry, NETs were large with extracellular DNA and MPO. For the clinical study group of >20% smudge cells, 88 were morphologically designated as NETs, 8 as DL vs. 59 as control group. A random sampling from >20% smudge cells showed cases with NET subclassification stained strongly with myeloperoxidase, neutrophil elastase and SytoxGreen while DLs were negative. Comparing patients with >20% smudge and NET sub-classification to Conclusions Our study was able to identify NETs on peripheral smears performed by a routine Hematology Autoanalyzer using a reliable set of morphologic characteristics, immunohistochemical stains and flow cytometry. It supports data that associate NETs with infections in the absence of leukocytosis. AI-Heme-1 was able to identify NETs on blood smears. This approach can provide a rapid, early and accurate tool to screen patients with infections.

Background. Neutrophil Extracellular Traps (NETs) are composed of extracellular decondensed chromatin networks that play an important role in immune and inflammatory response regulation. Simple and reliable identification of NETs has been challenging. Automated analyzers such as the CellaVision® Hematology Autoanalyzer identify a subset of cell-derived entities as smudge cells. We hypothesize that, in addition to the typical degenerated lymphocytes (DLs) forming smudge cells, a proportion of smudge cells as identified by the Autoanalyzer are actually NETs. Since patients with high numbers of NETs have increased and specific morbidities, accurate and rapid identification of NETs may be clinically useful. Methods. To test our hypothesis, we analyzed peripheral blood smears from samples processed by the CellaVision® Hematology Autoanalyzer. To differentiate NETs from DLs we used morphologic characteristics, immunohistochemistry, and flow cytometry. After immunohistochemistry and flow cytometry informed our morphologic classification of NETs and DLs, we relied solely on morphology. Smears with >20% smudge cells were classified as the study group; the control group had < 5% smudge cells. Medical chart review was performed by investigators blinded to sample group designation. Data obtained from chart review included patient demographics; presence of bacterial and/or viral infection occurring 10 and Fisher's exact tests for categorical variables with sample size Results. 155 samples were used in the analysis: 96 in the study group, 59 in the control group. Cell-derived entities staining strongly with myeloperoxidase (MPO), neutrophil elastase (NE), and leukocyte alkaline phosphatase (LAP) were classified as NETs. On flow cytometry, these NETs are at least twice as large as WBCs, display extracellular DNA (as identified by Sytox dye) and stain positively for MPO [Figure 1]. On Wright-Giemsa stain, these appeared morphologically as cell remnants with decondensed nuclei, no intact cytoplasm, dispersed granules, and polarized chromatin projections that resemble spider webs [Figure 2]. Of 96 patient samples with >20% smudge cells, morphologic analyses designated 88 as NETs and only 8 as DLs. Comparing patients with >20% to 20% smudge cell group had a neutrophils >8.5 x109/L. Of 13 infants 20%smudge cells, 5 had a bacterial infection with normal neutrophil counts. When the smudge cells were separated according to their category, NETs vs DLs, the DL group was older, had more LPD, higher total WBC, lymphocyte and monocyte counts (p=0.000044, 0.00036, 0.018, 0.022, 0.033) [Table 2]. Slides with mostly NETs had higher LAP scores than those classified as mostly DLs (172 +30.5 vs 103.3 +30.8, p=0.0087). Conclusions: NETosis is a relatively newly discovered tool in the neutrophil's arsenal. This study is the first to identify NETs on peripheral smear evaluations as performed by a routine Hematology Autoanalyzer and to differentiate them from DLs using a reliable set of morphologic characteristics, immunohistochemical stains, and flow cytometry probes. This study also supports data that associate NETs with bacterial infections. This could be clinically useful in diagnosis of infection in the absence of leukocytosis. Disclosures Billett: Albert Einstein College of Medicine: Patents & Royalties: Patent application pending for NETs AI software. Kushnir:Janssen Pharmaceuticals: Research Funding. Reyes Gil:Albert Einstein College of Medicine: Patents & Royalties: Patent application pending for NETs AI software.

Background: Patients with polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF) are at increased risk of thrombosis. These myeloproliferative neoplasm (MPN) patients are historically treated with vitamin K antagonists (VKAs) to prevent recurrent thromboembolic events. Direct oral anticoagulants (DOACs) are novel anticoagulants that are being increasingly used in MPNs without robust evidence. We hypothesize that DOAC and VKA therapy have similar efficacy and safety in MPNs with a comparable incidence of recurrent thromboembolic and bleeding events. Methods: Using Looking Glass®, an interactive software that integrates demographic and clinical datasets for the purpose of clinical research, we identified MPN patients who were on systemic anticoagulation (AC) therapy for a documented arterial or venous thrombotic event between 1/1/2014 and 4/1/2019. Medical charts were reviewed to obtain patient demographics, MPN subtype, mutation status, date of MPN diagnosis, date and site of index thrombosis, date of AC initiation, last documented date of therapy, date and site of recurrent thrombosis, changes in therapy; date and type of major bleeding (MB) and clinically relevant non-major bleeding (CRNMB) events on AC. Primary outcome was incidence of recurrent thrombotic events while on AC. Secondary outcome was the incidence of MB and CRNMB events. Statistical analyses were performed using two-sided t-tests with α =0.05 for continuous variables, chi-square for categorical variables with samples size >10 and Fisher's exact tests for categorical variables with sample size Results: We identified 53 patients that met the study criteria. Data on demographics, MPN subtype, mutation status, index thrombosis site, and type of AC are reported in Table 1. The majority of the patients in our cohort were females (69.8%), had a diagnosis of ET (71.7%), were JAK2V617F mutated (69.8%), and had a venous index event (75%). Median age for the entire cohort was 66.8 years (IQR 48.1-74.5) while the median age for those who had a recurrent thrombotic event on AC was 56.1 (IQR 46.4-76.1). If patients were switched from one anticoagulant to another, only the first treatment was included in the analysis. 31 (58.5%) of patients were on VKA therapy while 22 (41.5%) were on DOAC therapy. Median time of follow up was 227 and 451 days for DOACs and VKA respectively, (p = 0.01). Rates of thrombosis and bleeding were comparable within anticoagulation class. 5/22 (22.7%) and 6/31 (19.4%) of patients prescribed DOACs and VKA respectively developed recurrent thrombotic events. Median time to recurrent thrombotic event for DOACs as compared to VKA group was 568 vs 734 days (p = 0.29). 5/22 (22.7%) of those prescribed DOACs had bleeding events, 1 MB and 4 CRNMB. 11/31 (35.5%) of those prescribed VKA had bleeding events, 2 MB and 9 CRNMB. Median time to bleeding event for DOACs as compared to VKA was 56 vs 1347 days (p = 0.004). For the 53 patients on any anticoagulation, 11 (20.7%) patients had recurrent events while on AC (DOAC and VKA). In contrast, of the 14 patients who had AC therapy interrupted for any reason, 8 (57.1%) developed recurrent thrombotic events (p = 0.02). Table 2 summarizes these findings. Conclusion: We conducted a retrospective chart review study comparing the incidence of recurrent thromboembolic events on DOAC and VKA therapy. This is the largest study to date of MPN patients treated with DOACs. Based on our data, it appears that patients treated with DOACs have a comparable incidence of recurrent thrombosis and hemorrhagic events when compared to VKA therapy, although our study suggests that bleeding events may occur sooner in patients treated with DOACs. A large percentage of people with interruptions in their AC developed recurrent thrombotic events. Our data further emphasize the profound pro-thrombotic nature of MPN and therefore the need for uninterrupted anticoagulation therapy. Overall, given the comparable incidence of thrombosis and hemorrhage, DOAC therapy appears to be similar to VKA therapy in management of thrombotic complications of MPNs. The limitations of our study were as expected: a small sample size and significantly shorter median time for DOAC follow up as compared to VKA. Future, prospective large-scale studies are needed to confirm the safety and efficacy of DOAC therapy in MPNs. Disclosures Kushnir: Janssen Pharmaceuticals: Research Funding. Billett:Bayer Pharmaceuticals: Research Funding; Janssen Pharmaceuticals: Research Funding; Albert Einstein College of Medicine: Patents & Royalties: Patent application pending for NETs AI software.