Hematologic Conditions Research Articles

Predicting Disease Progression from Idiopathic Cytopenia of Undetermined Significance to Myeloid Malignancies Using a Machine Learning-Based Approach

Background Idiopathic cytopenia of undetermined significance (ICUS) is characterized by an unexplained, persistent cytopenia without a definite diagnosis of hematologic or non-hematologic conditions, and that does not meet criteria for myeloid neoplasms. The progression of ICUS to myeloid malignancies has been associated with certain clinical features, such as genetic mutations or allele frequencies. However, the incidence of progression and the risk factors vary among previous studies. While prognostic scoring systems are well-established in myelodysplastic syndrome (MDS) to predict progression to acute myeloid leukemia and survival outcomes, similar predictive tools for ICUS are currently lacking. Considering that a significant proportion of patients with ICUS share similar genetic abnormalities and clinical features with those with MDS, there is a need for predictive tools for ICUS. In this study, we aimed to establish a predictive model for disease progression from ICUS to myeloid malignancies. Methods Patients with ICUS were identified using electronic medical records, and those meeting the diagnostic criteria of ICUS were included. ICUS was defined as persistent cytopenia lasting for at least 4 months, with no underlying disease or condition that could explain the cytopenia which included history of cytotoxic chemotherapy or radiation therapy, blood or bone marrow (BM) disorders, autoimmune diseases, solid organ transplantation, active infection by atypical pathogens, and the use of immunosuppressant and chemotherapeutic agents. Cytopenia was defined as follows: hemoglobin <13 g/dL in males or <12 g/dL in females, neutrophil count <1.9 × 10 9/L, and/or platelets <150 × 10 9/L. For the predictive model, various features were considered, including medication history, laboratory data, comorbidities, family history of cancer and major disorders, smoking history, alcohol consumption, and physical measurements. Numeric data from the BM report were standardized using regular expressions, while free text or comments from the BM report and chromosomal analysis were extracted and processed using a pre-trained language model called PubMedBERT to generate embeddings. The primary objective of this study was to develop a predictive model for identifying progression from ICUS to myeloid malignancies. The performance of the model was assessed using machine learning algorithms, specifically XGBoost, support vector machine, and logistic regression. Results Among the initial 6,962 patients with medical records of the BM examination between January 2000 and December 2021, 5,147 patients were excluded from the modeling process due to secondary causes of cytopenia. Ultimately, 1,815 patients were finally included in the study. Of 1,815 patients, 47 (2.6%) were diagnosed with myeloid malignancies from further BM examination. The predictive model, utilizing XGBoost and incorporating standardized text and embedded features, demonstrated favorable performance, with a mean area under the receiver operating characteristic curve of 0.800 (Figure). Additionally, our analysis confirmed that the XGBoost model effectively processed features from text data, as we assessed the feature importance using Shapley values. Conclusion In conclusion, our study successfully established a predictive model for disease progression from ICUS to myeloid malignancies, demonstrating the potential utility of clinical predictive tools. Further integration of genetic data holds promise for enhancing the model's performance and providing clinical insights for managing patients with ICUS.

An 8-Year Retrospective Review of Human Albumin Solution (HAS) Use August 2015 to March 2023; Guy's and St Thomas' NHS Foundation Trust (GSTFT)

Abstract Background: HAS is widely used in clinical practice for a variety of haematological, renal, neurological, respiratory and metabolic conditions. A United Kingdom shortage in 2015 prompted a demand management guideline incorporating the American Society for Apheresis (ASFA) indications 1 and GSTFT criteria 2 for other indications. Objectives:The objective of this study was to evaluate the indications for HAS usage following the introduction of the GSTFT demand management guideline. Methods: We audited HAS usage from August 2015 to March 2023 at GSTFT. Data was entered in SPSS version 20, with categorical variables described as frequencies and percentages. Results: 4816 patients received HAS during the study period, totaling 21,231 infusions. We recorded 16,772 (79%) infusions for 20% HAS in 4,145 patients. The indications for 20% HAS included; volume resuscitation for hypovolaemia 5237 (31%), severe sepsis/septic shock 3528 (21%), acute lung injury and severe respiratory failure 2987 (18%), paracentesis 2402 (14%), hepatorenal syndrome 1710 (10%), childhood nephrotic syndrome 685 (4.1%) and spontaneous bacterial peritonitis 223 (1.3%) (Table 1). According to GSTFT criteria infusions were recorded in the following indication categories: Red 7099 (42.3%), Blue 4436 (26.4%) and Grey 5237 (31.2%). A total of 4459 (21%) infusions were recorded for 4.5 and 5% HAS. A total of 3628 (81%) infusions were used for plasma exchange (PEX) in 305 patients; 2817(76.99%) ASFA category I, 445(12.03%) category II, 290(7.97%) category III and 92 (2.5%) for indications not specified according to ASFA; 826 infusions (18.5%) were for volume resuscitation for hypovolaemia (Grey indication) in 389 patients, the remaining 5 infusions (0.1%) were in 3 patients for burns and thermal injuries (Table 1). Major indications for PEX included post-transplant focal segmental glomerulosclerosis 911 infusions (20%) in 9 patients, familial hypercholesterolaemia 738 infusions (16%) in 5 patients, antibody mediated rejection 439 infusions (10%) in 71 patients (Table 2). Conclusions: This report provides a rare long term retrospective review of total albumin usage in a large UK tertiary referral center. The majority (97.5%) of PEX HAS indications were within ASFA guidelines. Aside from apheresis the main indication for HAS was volume resuscitation, a grey indication, where evidence is weak. REFERENCES (1) Padmanabhan A, Connelly-Smith L, Aqui N, Balogun RA, Klingel R, Meyer E, Pham HP, Schneiderman J, Witt V, Wu Y, Zantek ND, Dunbar NM, Schwartz GEJ. Guidelines on the Use of Therapeutic Apheresis in Clinical Practice - Evidence-Based Approach from the Writing Committee of the American Society for Apheresis: The Eighth Special Issue. J Clin Apher. 2019 Jun;34(3):171-354. doi: 10.1002/jca.21705. PMID: 31180581 (2) Yazdani MS, Retter A, Maggs T, Li P, Robson MG, Reid C, Holmes P, Garood T, Robinson SE. Where does the Albumin go? Human Albumin Solution usage following the implementation of a demand management programme. Transfus Med. 2017 Jun;27(3):192-199. doi: 10.1111/tme.12406. Epub 2017 Apr 3. PMID: 28370709.

Outpatient Management of Sickle Cell Vaso-Occlusive Crisis As a Strategy of Decreasing Emergency Department Visits

Background: Complications of sickle cell disease (SCD), including vaso-occlusive crises (VOC), usually require emergency room visits or even hospitalization for management. Outpatient treatment programs have been developed for management of VOC, however the literature is limited as to the efficacy of these models. Previously, patients in Edmonton, Canada followed by the Hemoglobinopathy Clinic would have to present to the emergency department (ED) for assessment of and management of VOC. Since 2019, patients experiencing early VOC symptoms were able to present to the Medical Outpatient Unit (MOU), an infusion clinic shared with other benign and malignant hematology conditions, to be assessed and receive treatment. This study retrospectively evaluated the outcomes of this treatment strategy. Hypothesis: Outpatient management of VOC is an effective way to assess patients and provide appropriate treatment, thereby reducing the frequency of ED presentations for SCD patients. Methods: Patients were able to schedule their own appointments and were encouraged to present early before they developed severe symptoms. They would be assessed by a nurse, who could then release orders from their personalized pain plan, which is a standing set of orders from an SCD clinic physician. Examples of orders include intravenous fluids and pain medications. Based on the severity of symptoms, patients could also be referred to the ED or for assessment by a physician or nurse practitioner. Chart review of patients aged 18 years or older with SCD followed by the Edmonton Hemoglobinopathy Clinic and who presented to MOU from November 2019 to December 2022 for management of VOC was completed. Information gathered included if the patient was on hydroxyurea at the time, investigations ordered, treatments administered, if NP or physician assessment was required, and disposition following the encounter. Encounters within 7 days were counted as one episode and assumed to be the same VOC event. Visits to ED for this cohort were counted and compared to the number of ED visits from 2016 to 2018. Results: 26 SCD patients had at least one MOU encounter for VOC or prophylaxis resulting in a total of 136 encounters (median 2, maximum 25). These accounted for 96 separate episodes of VOC (median 2, maximum 19), with a median of 1 encounter to MOU per episode (maximum 5). Patient demographics had a mean age of 32 years as of the beginning of the study (maximum 65, minimum 16) with 14 males (54%) and 12 females (46%). Patient diagnoses included 10 with HbSS (38%), 12 with HbSC (46%), 3 with HbSD (12%), and 1 with HbSB° (4%). 21 of 26 patients (81%) were on hydroxyurea at some point during this time period. IV fluids were administered in 129 encounters (95%), and pain medications were given in 64 encounters (47%), with opioid medications being given in 24 encounters (18%). 109 encounters had assessment by a nurse only (80%), while 24 were also assessed by a nurse practitioner (18%) and only 3 required assessment by a physician (2%). Patients were discharged home in 134 of 136 encounters (99%), with only 2 encounters resulting in assessment in ED. 70 of 96 episodes of VOC treated in MOU did not have presentation to ED within 30 days (73%). Total ED visits for this cohort decreased from 59 in 2016-2018 to 38 during the time of this study. Conclusion: Treatment of VOC in an outpatient setting was effective for assessment and treatment and decreased ED visits in our cohort. While retrospective, these results suggest outpatient treatment of VOC can be completed safely and efficiently in a shared infusion unit and may be generalized to other centres with outpatient IV infusion programs.

Mortality and Comorbidities of Covid-19 Patients with Immune Thrombocytopenic Purpura - a Review of the National Database 2019-2020

Introduction: Immune thrombocytopenic purpura (ITP) is a diagnosis of exclusion that is characterized by isolated thrombocytopenia with a generalized purpuric rash. If there is a known case for the ITP, it is referred to as secondary ITP. Secondary ITP may often be caused by drugs, systemic immunologic, or infectious diseases. Covid-19 is a disease caused by the SARS-CoV-2 virus, which caused a pandemic in 2020, affecting hundreds of millions of people worldwide. There have been several different hematologic conditions associated with this viral infection, including deep vein thromboses, pulmonary emboli, and many patients with ITP induced by Covid-19. With several case reports and case series available on these patients, the specifics behind the strength of the association, mortality of the patients, and their comorbidities have not been previously explored. Methods: Using the national inpatient sample from the years 2019-2020, we analyzed adult hospitalized patients with ITP and Covid-19 based on their International Classification of Diseases - 10 clinical modification codes. We calculated the odds ratios for patients with Covid-19 being diagnosed with ITP compared to other hospitalized patients. Additionally, we calculated the odds of several complications, treatments, as well as concurrent conditions in patients with Covid-19 and ITP. The complications measured were epistaxis or hemoptysis, intracranial hemorrhage (ICH), non-intracranial hemorrhage (nICH), deep vein thrombosis (DVT), pulmonary embolism (PE), and death. Treatments measured were transfusion with either red blood cells (RBC) or platelets. The concurrent conditions evaluated were systemic lupus erythematosus (SLE), hepatitis C and heparin-induced thrombocytopenia (HIT). Results Out of the 115,150 hospitalized patients with ITP included in the database, 0.02% of them were diagnosed with Covid-19. The odds of a patient with Covid-19 being diagnosed with ITP were lower than those for other hospitalized patients (OR=0.860 [0.787-0.941], p=0.001). The mean age for patients with ITP diagnosed with Covid-19 was 64.1 compared to 60.9 in patients without Covid-19 (p=0.001). Hospitalized patients with ITP who were also diagnosed with Covid-19 were at a higher risk of developing epistaxis (OR: 1.45 [1.01-2.07], p=0.042), pulmonary embolism (OR: 2.22 [1.35-3.66], p=0.002), and death (OR: 4.39 [3.33-5.80], p<0.001) compared to those without Covid-19. They were not at higher odds of developing a DVT (OR: 1.25 [0.798-1.97], p=0.325), ICH (OR: 0.158 [0.0160-1.56], 0.114) or nICH (OR: 1.03 [0.678-1.55], p=0.905). They were not significantly more or less likely to get transfused with RBC (OR: 0.816 [0.585-1.14], p=0.231) or platelets (OR: 1.14 [0.865-1.53], p=0.337). The ITP patients with concurrent Covid-19 were also not more likely to suffer from SLE (OR: 0.737 [0.453-1.20], p= 0.222), Hepatitis C (OR: 0.760 [0.392-1.47], 0.416), or HIT (OR: 1.16 [0.181-7.49], p=0.872). Conclusion Hospitalized patients with Covid-19 were at a lower risk of being diagnosed with concurrent ITP than other hospitalized Covid-19 patients. Those with ITP who also had Covid 19 had significantly higher odds of complication of bleeding with epistaxis or hemoptysis as well as a higher risk of pulmonary embolism and death. However, they were not at higher risk of hemorrhage elsewhere or DVT. They were not treated with transfusions differently and having SLE, hepatitis C or HIT did not place hospitalized patients with ITP at a higher risk of developing Covid-19.

Defining the Impacts of Iron Overload in Children Receiving Hematopoietic Stem Cell Transplantation for Non-Malignant Hematologic Conditions

Background: Hematopoietic stem cell transplant (HSCT) is curative for patients with non-malignant blood disorders. Children with these conditions often require numerous red blood cell transfusions prior to HSCT, leading to iron overload. It has been hypothesized that pre-HSCT iron overload leads to poorer post-HSCT outcomes, and studies have demonstrated a prognostic link between portal fibrosis, hepatomegaly, and post-transplant survival in thalassemia. Ferritin and liver iron concentration (LIC) are used as surrogate markers of iron overload to determine eligibility for HSCT, but neither has been definitively associated with poorer HSCT outcomes in this population. Further, patients receiving HSCTs for non-malignant conditions may require post-transplant iron reduction therapy (IRT), but whether chelation or phlebotomy is more effective in reducing iron overload is unknown. Objectives: In children with non-malignant blood disorders, determine if higher pre-transplant ferritin and LIC are associated with poorer post-HSCT outcomes including GVHD-free, relapse-free survival (GRFS), overall survival (OS), higher rates of veno-occlusive disease (VOD), and longer neutrophil and platelet engraftment times. Determine whether post-HSCT chelation or phlebotomy is associated with a faster rate of ferritin reduction. Methods: We conducted a single-center retrospective cohort study of children with sickle cell disease, beta thalassemia major, aplastic anemia, and other disorders requiring RBC transfusion from a large pediatric academic center from 2010-2023 as a pilot study for our in-progress multi-center analysis. GRFS and OS were compared using a Kaplan-Meier survival analysis. GRFS analysis excluded autologous SCTs. Engraftment times were compared using a competing risks analysis. VOD rates were compared using logistic regression. Rate of ferritin reduction was analyzed using a Wilcoxon Rank-Sum test. Statistical analyses were conducted using StataBE v17.0. Results: Among 152 patients with non-malignant blood disorders who underwent HSCT, 136 patients received allogeneic SCTs and 16 received gene-modified autologous SCTs. 90 patients had a pre-transplant LIC <5mg/g dry tissue or if no LIC was available, ferritin <1000ng/mL (low iron). 41 patients had a pre-transplant LIC of 5-10mg/g dry tissue or ferritin 1000-3000ng/mL (moderate iron). 21 patients had a pre-transplant LIC ≥10mg/g dry tissue or ferritin ≥3000ng/mL (high iron). GRFS rates were 20% for the low iron group, 13% for moderate iron, and 22% for high iron, and were not statistically distinct ( p = 0.55). OS was 92.2% for low iron, 97.6% for moderate iron, and 95.2% for high iron. Survival analysis showed no significant difference in OS ( p = 0.51). Minimum detectable hazard ratios were 2.00 and 1.92 comparing high and low iron groups for GRFS and OS, respectively. Logistic regression showed an odds ratio of 3.25 for VOD in high iron versus low iron in patients who received busulfan, though this was not statistically significant, p = 0.38. Median time to neutrophil engraftment did not differ among groups (15 days for low iron, 15 days for moderate and 14 days for high). Median time to platelet engraftment was 18 days for low iron, 19 days for moderate iron and 26 days for high iron, though due to wide variance in engraftment times, this was not statistically significant ( p = 0.81). 11 patients underwent post-HSCT IRT with chelation and 12 with phlebotomy. Median rate of ferritin reduction for patients receiving post-HSCT chelation was 53 ng/mL/month on therapy, compared to 64 ng/mL/month for those who received phlebotomy ( p = 0.24). Conclusions: In this pilot study, higher pre-transplant LIC and ferritin were not significantly associated with poorer post-transplant outcomes. Patients in the high iron group showed a trend toward increased VOD risk and longer time to platelet engraftment, but GRFS and OS were not impacted. Post-HSCT phlebotomy and chelation showed similar rates of ferritin reduction as a marker for elimination of residual iron overload. These data suggest a need to reevaluate the utility of LIC and ferritin as prognostic markers for HSCT risk. Additional data are needed to determine if IRT targeting specific iron thresholds is truly needed prior to HSCT. This pilot study informs our in-progress multi-center analysis of the impact of iron overload on post-HSCT outcomes in children with non-malignant blood disorders.

Enhancing Bone Marrow Biopsy Sample Quality: A Comprehensive Quality Improvement Study at UNM Cancer Center

Introduction Adequate samples from bone marrow biopsies are required for pathologists to diagnose and monitor hematologic conditions accurately. These biopsies involve the extraction of bone marrow samples in two main forms: an aspirate and a core biopsy. In some cases, additional molecular testing may be conducted for the purposes of diagnosis and classification. The journey of a bone marrow sample from the patient's bedside to the laboratory is a complex process that involves the collaboration of numerous participants and interconnected systems to ensure the integrity and accuracy of the results. At our cancer center, we initiated a quality improvement (QI) project to assess the baseline success rate of bone marrow sample collection, identify areas for improvement in collection, form and implement targeted interventions, and then measure the project's success. Methods In this QI study, we utilized an A3 model which included 1) assessing the current state of bone marrow biopsy samples at our institution 2) reviewing the current process of collection 3) analysis to identify the root causes affecting quality 4) Identifying our goal state 5) implementing interventions to improve the quality and 6) follow up to evaluate the effectiveness of our interventions against the stated goal. To identify the current state, we assessed the quality of 101 bone marrow biopsy samples collected from May to October 2022, focusing on the aspirate, clot, and biopsy sections. Two pathologists reviewed 20 of these samples at random to re-read them and defined inadequate aspirate and clots as those which were ‘aspicular’ or ‘paucispicular’ and inadequate trephine biopsies as those that were reported as ‘limited’ or ‘inadequate’ for interpretation. This limited analysis was hypothesis generating and we relied on descriptions of aspirate quality and core length in the biopsy reports for the remaining samples. We observed different providers and technicians performing bone marrow biopsies to understand the current process of collection across our institution. Our system analysis identified the following issues: Non-standardized collection technique, communication errors between technicians and providers in terms of core length and aspirate adequacy, and technician proficiency in identifying spicules and core length To address these issues, we wrote a guideline outlining the recommended standard technique and performed a training for all providers. This guideline included a standard communication guideline between technicians and providers. Technicians underwent additional training in terms of identifying spicules and measuring core length. We set a pre-defined goal of success as 70% adequacy for bone marrow biopsy aspirates and 90% adequacy for core biopsies. Following our interventions, we started collecting post-intervention bone marrow biopsies in May 2023 and plan to evaluate the adequacy of 100 bone marrow samples Results Samples were categorized as those performed by interventional radiology (IR) providers and non-IR providers (advanced practice providers, attendings, and fellows).At baseline, the adequacy rates for aspirate, clot, and biopsy sections were 35%, 36%, and 87%, respectively, for IR providers, and 63%, 70%, and 67%, respectively, for non-IR providers. (Table 1)We plan to evaluate 100 samples post-intervention and to date, we have evaluated 20 samples. Among IR cases, adequacy rates for aspirate, clot, and biopsy sections were 69%, 85%, and 92%, respectively. For non-IR cases, adequacy rates were 86%, 100%, and 86%, respectively. (Table 2) Although additional samples are needed to confirm our results, there is thus far a noticeable improvement in the rate of adequate sample collection for both IR and non-IR providers. While not included in the current analysis, we plan to add patient factors that may affect sample collection such as Body Mass Index or use of sedation in our final analysis to address potential confounders. Conclusion Through our QI study, we aimed to enhance the quality of bone marrow biopsy samples at our institution. Preliminary results demonstrate improvements in the rate of adequate sample collection for aspirate and core biopsies following our quality interventions. Future studies will explore the impact of patient and disease factors on sample quality and also assess whether the improved outcomes are sustained at a later point in time with additional follow up.

Unravelling the Mechanism behind Ineffective Erythropoiesis in Sickle Cell Disease: The Role of GATA-1

Background & Objectives: Ineffective erythropoiesis (IE) is an important factor in many types of anemias, including beta-thalassemia. Recently, a study by El Hoss et al provided compelling evidence for IE being an important part of the pathophysiology of sickle cell anemia (SCA) (PMID: 32855279). Furthermore, we developed a clinical index to measure IE and showed that patients with the SS genotype, but not SC, had increased IE compared to healthy donors (HD) (PMID: 34670360). However, the molecular mechanisms of IE in SCA, its relationship to disease heterogeneity and its potential as a therapeutic target, remain unknown. Importantly, GATA1, an essential erythroid transcription factor known to be downregulated in haematological conditions presenting with IE, has not been previously investigated in SCA. Thus, the aim of this project is to investigate the molecular basis of IE in SCA by focusing on GATA1 functions in erythropoiesis. Methods: HUDEP-2 cells, gene-edited sickle HUDEP-2 (SS HUDEP-2) (PMID: 32405513) cells and CD34+ cells isolated from individuals with HbSS and healthy donors, were differentiated ex vivo using a two-phase culture and (i) erythroid differentiation kinetics, (ii) markers of oxidative stress, (iii) GATA1 expression and (iv) antioxidant response factors NRF2, FOXO3 and heme-oxygenase 1 (HO-1) were assayed every other day during phase 2. IE was also studied in SS Berkeley transgenic mouse (PMID: 16166585). Both the spleen and the bone marrow were investigated in AA, AS and SS mice. Results: No significant differences were observed in the differentiation kinetics and in levels of oxidative stress in in vitro differentiated HUDEP-2 and SS HUDEP-2 cells. Moreover, GATA1 levels were similar in both cases. Importantly, ex vivo differentiation of human SS CD34+ cells showed a striking delay accompanied by high oxidative stress and a decrease in GATA1 protein levels (Figure 1) compared to normal controls. We also found a significant decrease in FOXO3, NRF2 and HO-1 levels in SS erythroblasts compared to healthy donor erythroblasts. IE was evident in SS mice compared to AA and AS controls. SS mice presented with higher levels of reactive oxygen species (ROS) in both the bone marrow and the spleen tissue. Histological studies showed that the SS Berkley mouse has a very congested bone marrow with a disorganized architecture. Moreover, we showed a significant decrease in GATA1 protein in SS spleen and bone marrow erythroid cells. Conclusion: Using ex vivo differentiation of primary SS cells and an in vivo mouse model for SCA, we show for the first time that aberrant GATA-1 levels play a key role during IE in SCA. During SS erythropoiesis, a significant reduction in the protein levels of the GATA1 erythroid master transcription factor and of FOXO3 and NF-E2, important transcriptional regulators of the oxidative stress response occur. These same changes were not seen in SS HUDEP-2 cells, suggesting that abnormalities of the bone marrow niche are central to abnormal erythropoiesis in SCA. Modification of the bone marrow niche and manipulation of GATA-1 levels may be important therapeutic tools in SCA.

Pathogenetic Subtypes of Pure Red Cell Aplasia and Therapeutic Management Strategies : A Single Centre Experience in the United Kingdom of 75 Patients over 10 Years

Introduction Pure red cell aplasia (PRCA) is a syndrome characterised by a severe anemia, reticulocytopenia and severe depletion of erythroid precursors in an otherwise unremarkable bone marrow. PRCA arises congenitally in Diamond-Blackfan Anemia and usually presents in childhood. Acquired PRCA can occur at any age, can be transient due to infections such as from parvovirus B19, or more chronic, secondary to autoimmune conditions, malignancies especially thymoma, erythropoiesis stimulating agents, , pregnancy and ABO incompatible hematopoetic stem cell transplantation. PRCA is also known to arise from drug and toxin exposure. Haematological malignancy/clonal disorders for e.g. CLL, MGUS, T-LGLs have well known associations with PRCA. PRCA can also be a feature of myelodysplastic syndrome and can herald evolution to aplastic anemia. Despite the heterogeneity in aetiology, the mainstay of treatment remains immunosuppression with steroids and/or ciclosporin. Here, we report our single centre experience of a large cohort of 75 patients with PRCA, referred to our centre over a 10 year period. Methods Patients with pure red cell aplasia referred to the Department of Hematological Medicine at King's College Hospital were identified by interrogation of the Electronic Patient Record (EPR) and pathology systems. The search terms used were a clinical or pathological diagnosis of ‘pure red cell aplasia’ or ‘PRCA’. Our hospital receives diagnostic samples from the South East of England, therefore data was collected only for patients with clinical information available. Patients (n=33) who developed PRCA post-allogeneic stem cell transplant were excluded. Results A total of 75 patients with both a pathological diagnosis of PRCA and available clinical information were identified, 31 (41.3%) were female. Median age was 51 years (range 9 - 84). The majority of patients had underlying conditions known to be associated with PRCA. Of the haematological conditions, PRCA was most seen in association with MDS (Table 1). Of the 75 patients in our cohort, 82% (61/75) required treatment for PRCA and 57% (43/75) required two or more lines of therapy. In total 25.3% (19/75) patients received corticosteroids as first line therapy. Of those, 75% showed a response, with 50% achieved a complete response. The response rate was less favourable (57%) in those patients in whom ciclosporin was used as first line therapy. Most common second line therapy was Ciclosporin (22.3%) followed by Cyclophosphamide (4%), Sirolimus (2.7%) and Anti-Thymocyte Globulin (1.33%). Of the cohort with an underlying MDS, 52% (11/21) responded to treatment, compared to 65% of those with idiopathic PRCA, likely reflective of the recalcitrant nature of PRCA in MDS. Other therapies received were IVIG, erythropoietin and disease-directed therapy,e.g lenalidomide for MDS with 5q- and thymectomy. Median follow of patients were 42 months.The overall survival of PRCA since last follow up was 50% for the cohort as a whole and 63% for those without an associated malignancy or clonal disorder. D iscussion In this large single centre experience of PRCA, we describe a lower incidence of idiopathic PRCA, lower median age despite a large proportion of MDS and increased incidence in male as compared to published literature. Response to initial therapy was seen in the majority of idiopathic PRCA patients, however response was lower in patients with an underlying malignancy. Of note we identified STAT3 mutations in two patients, highlighting the role of molecular testing and keeping a broad differential diagnosis when presented with this rare condition.

TCRαβ +/CD19 + - Depleted HLA-Haploidentical Hematopoietic Stem Cell Traansplantation in Pediatric Patient with Fanconi Anemia

Background Allogeneic hematopoietic stem cell transplantation (HSCT) currently represents the only proven treatment able to rescue bone marrow failure and prevent the occurrence of clonal evolution in patients with Fanconi Anemia (FA). If HSCT from HLA-identical related donor (MRD) is reported to be associated with better outcomes, this is not available for most patients. On the other hand, the identification of a fully matched unrelated donor (MUD) may be unsuccessful, or require times incompatible with a prompt treatment of the haematological condition. For patients who lack a MRD or MUD, the preferred donor choice is debated. HLA partially matched haploidentical donor (haplo) is virtually immediately available for all patients and haplo-HSCT has been reported over the last few years as a promising alternative for those patients. Following the favorable results already reported from our group of a cohort of pediatric and young adult FA patients underwent haplo-HSCT, based on the selective depletion of TCRαβ + and CD19 + cells graft manipulation, here we present the outcome of an enlarged cohort of patients who received HSCT in 3 different centers. Methods Patients diagnosed with FA and eligible for an allogeneic transplantation, but lacking a MRD or MUD, and with a suitable HLA-haploidentical donor were eligible to this study. The conditioning regimen included intravenous fludarabine, cyclophosphamide and single-dose total body irradiation for most patients. Pretransplant anti-T-lymphocyte globulin was administered in all patient to control in vivo bidirectional donor-recipient alloreactivity. Apheresis and graft manipulation were performed as previously reported (Li Pira, Biol Blood Marrow Transplant 2016). Results Thirty-five patients (19 males and 16 females) underwent haplo-HSCT between September 2011 and April 2023 in 3 different centers (Bambino Gesù Children's Hospital, Rome, Italy; Policlinico San Matteo, Pavia, Italy; Tokyo; National Center for Child Health and Development, Children's Cancer Center, Tokyo, Japan). Twenty-four patients have been previously reported (Strocchio, Blood Adv 2021). Details on patients and donor characteristics, graft composition and conditioning regimen are listed in table 1. One patient with clonal evolution and 1 with AML received fludarabine and AraC 3 weeks before the start of the conditioning. Primary engraftment was achieved in 33 patients (94.3%), with median time for neutrophil and platelet recovery of 12 days (range, 9-20 days) and 10 days (range, 7-14 days), respectively. Primary graft failure occurred in 2 patients and both were successfully transplanted from the other haploidentical parent. The monitoring of chimerism analysis confirmed a stable engraftment of donor hemopoiesis in all engrafted patients. Within 33 evaluable patients, 9 (27.3%) experienced grade 1-2 aGvHD (7 with stage I-II skin-only involvement, 1 with stage I lower gastrointestinal involvement) at a median time of 35.5 days (range, 16-67 days) after HSCT. One patient developed late-onset skin only grade 2 aGvHD at day +211 after HSCT. One patient (3%) experienced grade IV aGvHD (liver and gastrointestinal involvement) at day + 100 from HSCT, 4 weeks after the infusion of adenoviral-specific donor T cells; he is currently receiving ruxolitinib and the complete resolution of GvHD was obtained. Only one patient (3%), developed cGvHD with mild skin involvement. Thirteen patients (39.4%) experienced one or more viral infections or reactivations (6 cytomegalovirus, 4 herpesvirus-6, 2 adenovirus, 1 parainfluenzae); the specific antiviral treatment was administered with a complete resolution of infection in all cases. With a median follow up of 5.5 years (range, 0.6-11.4 years) all the patients are alive and with resolution of hematological complications. Except for the already reported vulvar intraepithelial neoplasia, no additional posttransplant malignancy was observed Conclusions Our data obtained from enlarged cohort of patients previously reported, confirm excellent results in terms of survival and a good rate of engraftment also in a multicenter setting. The low incidence of acute and chronic GvHD, a particularly detrimental complication in patients with DNA repair disorder, makes this approach attractive in this patient population. In FA patients lacking a standard donor, TCRab +/CD19 + haplo-HSCT is confirmed to be a promising strategy.

A Real-World Evidence Review of Post-Marketing Safety and Compliance with Pegcetacoplan in Patients with Paroxysmal Nocturnal Hemoglobinuria (PNH) in the US

Introduction: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare, acquired hematologic condition characterized by complement-mediated, life-threatening hemolysis and thrombosis which are associated with significant impacts on health-related quality of life (HRQoL). Pegcetacoplan is the first targeted complement component 3 (C3) therapy approved for adults with PNH (US) and adults with PNH plus anemia despite receiving a complement component 5 inhibitor (C5i) for ≥3 months (EU). In clinical trials including patients with PNH who were C5i-experienced or -naive, pegcetacoplan significantly improved levels of hemoglobin (Hb) and lactate dehydrogenase (LDH) and reduced transfusion burden. Pegcetacoplan had a favorable safety profile in parent studies and an ongoing long-term, rollover, open-label extension study (NCT03531255). Compliance with pegcetacoplan treatment was high across all clinical studies. In the US real-world OPERA and Adelphi PNH Disease Specific Programme™ (DSP) patient-reported outcomes (PRO) studies, improvements in levels of Hb and LDH, along with self-reported fatigue and cognitive outcomes, were observed. Pegcetacoplan treatment also led to reductions in the frequency and severity of PNH symptoms (including shortness of breath and fatigue) and improvements in social, physical, and emotional HRQoL domains in the US real-world Voice of the Patient PRO study. Further, both patient and physician satisfaction with pegcetacoplan treatment was high in the Adelphi PNH DSP study. However, to date, compliance and safety with pegcetacoplan treatment in the real-world setting have not been described. The objective of this real-world evidence review study was to evaluate compliance and safety with pegcetacoplan treatment in patients with PNH in the US post-marketing setting. Methods: Post-marketing data from the US, including the number of patients who received pegcetacoplan and reported safety events, were collected and analyzed from the pegcetacoplan Risk Evaluation and Mitigation Strategies (REMS) program which controls the distribution of pegcetacoplan and the pharmacovigilance safety database through May 13, 2023. Treatment compliance was calculated as the proportion of days a patient had the drug in possession, divided by the total number of days of follow-up, using central pharmacy prescription refill data. Thrombosis (a leading cause of death in patients with PNH prior to the availability of complement inhibitors) and meningococcal infections (a potential risk with complement inhibitors) were safety events of interest. To reduce the risk of serious meningococcal infections, clinical trial protocols and pegcetacoplan labeling required vaccination against Streptococcus pneumoniae; N meningitidis types A, C, W, Y, and B; and Haemophilus influenzae type B before starting treatment with pegcetacoplan. If pegcetacoplan treatment must be initiated before vaccination, the US label mandates prophylactic antibiotic use. In this study, the rates of thrombosis and meningococcal infection per 100 patient-years were estimated based on the total number of thrombosis and meningococcal infection events reported in the REMS program. Results: As of May 13, 2023, the cumulative pegcetacoplan exposure was 273.10 patient-years in the US post-marketing setting. Based on prescription refill data, compliance with pegcetacoplan treatment was ~98%. There were 2 confirmed thrombotic events reported and the incidence of thrombotic events was 0.73 events/100 patient-years in 273.10 patient-years. Similar to clinical trials, no meningococcal infections were reported in the US post-marketing setting. Conclusions: The high compliance rate and favorable safety profile of pegcetacoplan in the US post-marketing setting were consistent with clinical trial observations. These data, coupled with the effectiveness on hematologic parameters and improvements in symptoms and HRQoL reported in pegcetacoplan real-world PRO studies, support a positive benefit:risk profile for pegcetacoplan in the real-world setting.

Survival Outcomes of US Patients Diagnosed with CMML over the Past Two Decades, Analysis from the SEER Database

Background: CMML is a rare and one of the most aggressive forms of leukemias with hybrid features of myeloproliferative neoplasms (MPN) and myelodysplastic neoplasms/syndromes (MDS). Given its rarity and the fact that CMML was categorized previously as MPN or MDS, the true incidence of CMML is unknown. To the best of our knowledge, the largest and most up to date study addressing the incidence and survival outcomes of patients with CMML in the United States covered a period from 2000 to 2013, with a sample size of 2,238 patients. The aim of this study is to investigate the clinical characteristics, survival outcomes, and independent prognostic factors of patients with CMML over the past two decades with a larger sample size. Methods: A total of 4,124 patients diagnosed with CMML, between 2000 and 2017, were ultimately enrolled in our study by retrieving data from the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed demographics, clinical characteristics, and overall mortality (OM) as well as cancer-specific mortality (CSM) of HSTCL. Variables with a p value <0.01 in the univariate Cox regression were incorporated into the multivariate Cox model to determine the independent prognostic factors, with a hazard ratio (HR) of greater than 1 representing adverse prognostic factors. Results: Our cohort had a male predominance (61.57%). Most patients were diagnosed between the age of 60- and 79-year-old (55.16%) and CMML was least common among patients younger than 40 (1.41%). Non-Hispanic whites (79.03%) were most represented. Univariate cox proportional hazard regression analyses of factors affecting all-cause mortality revealedhigher overall mortality among patients 80 and older (HR= 2.68, 95% CI 1.89-3.79, p<0.01) followed by patients aged 60-79 (HR=1.85, 95% CI 1.31-2.62, p<0.01), patients living in nonmetropolitan counties not adjacent to a metropolitan area (HR=1.28, 95% CI 1.11-1.48, p<0.01), widowed patients (HR=1.42, 95% CI 1.30-1.54, p<0.01) and those that underwent chemotherapy (HR=1.20, 95% CI 1.13-1.29, p<0.01). Lower OM was observed in patients with yearly income of $75,000+ (HR=0.85, 95% CI 0.77-0.94, p<0.01) and those that undergo radiation (HR=0.64, 95% CI 0.47-0.87, p<0.01). CSM was higher among male patients (HR=1.12, 95% CI 1.03-1.22, <0.01), those aged 80 or older (HR=1.90, 95% CI 1.28-2.81, p<0.01), patients living in nonmetropolitan counties not adjacent to a metropolitan area (HR=1.30, 95% CI 1.10-1.54, p<0.01), widowed patients (HR=1.27, 95% CI 1.15-1.41, p<0.01), and those that underwent chemotherapy (HR=1.59, 95% CI 1.47-1.73, p<0.01). Multivariate cox proportional hazard regression analyses of factors affecting OM revealedhigher mortality in male patients, those 80+, patients living in counties in metropolitan areas of 250,000 to 1 million persons, single patients, widowed and those that underwent chemotherapy. Lower OM was found in patients with an annual income of $75,000+. CSM revealed a higher mortality in male patients, those aged 80+, patients living in counties in metropolitan areas of 250,000 to 1 million persons, single patients, widowed and those that underwent chemotherapy. Conclusion: CMML remains a rare and very dismal hematologic condition. In this United States population-based retrospective cohort study using the SEER database, we found that male sex, advanced aged, single, widowed and those that underwent chemotherapy are independent factors of poor prognosis. While one would expect older patients and those that require chemotherapy to have a poor prognosis as they have a baseline poor performance status and present at advanced disease respectively, it remains unclear why widowed/single and male patients are at higher mortality risk. Perhaps, for widowed and single patients, earlier involvement of family members and community support may lower their mortality. This data paves the way for larger prospective studies addressing factors associated with worse prognosis widowed/single and male patients.

ATP-induced Cell Death Mechanism

"ATP-induced cell death" is a novel form of cellular demise identified since 1991, typically characterized by a substantial accumulation of adenosine triphosphate (ATP) and the activation of ATP membrane receptors during the cell death process. The perturbation of ATP homeostasis is intricately linked to mitochondrial function. In recent years, ATP-induced cell death (AICD) has emerged as a discernible pattern of cell demise attributed to heightened levels of extracellular ATP (eATP). This phenomenon is intimately associated with the pathophysiological mechanisms underpinning a plethora of maladies, including malignancies, neurodegenerative disorders, ischemia-reperfusion injury, renal impairment, and hematological conditions. The strategic modulation of ATP-induced cell death to mitigate the onset and progression of these related diseases has garnered significant attention and stands as a focal point in etiological research and therapeutic interventions. Nevertheless, the functional alterations and precise molecular mechanisms governing ATP-induced cell death demand further comprehensive exploration. This paper comprehensively synthesizes the most recent advancements in the understanding of ATP-induced cell death mechanisms, with the overarching objective of serving as a reference for a deeper comprehension of its pathogenesis and the proposition of novel therapeutic targets for the management of associated diseases.

Simultaneous Robotic-Assisted Splenectomy and Cholecystectomy in Children: Is It Safe and Effective?

Background: Hematologic conditions such as hereditary spherocytosis, sickle cell disease, and idiopathic thrombocytopenic purpura are frequently linked to cholelithiasis. In instances where symptoms are present, simultaneous cholecystectomy and splenectomy are commonly recommended. Our aim was to assess the outcomes of robotic-assisted procedures conducted for simultaneous surgical issues involving the spleen and gallbladder in pediatric patients. Materials and Methods: We have made a simultaneous retrospective study of children with hereditary hematological diseases who underwent combined robotic-assisted splenectomy and cholecystectomy at our institution from January 2010 to December 2021. Demographics, clinical features, intraoperative data, length of hospital stay, postoperative complications, and follow-up outcomes were analyzed. Results: A total of 11 patients (6 male; 5 female) were included, with a mean age of 13.9 ± 4.4 years (range 8-17). Hereditary spherocytosis was the most common disease (7 cases), followed by sick cell disease (4 cases), with associated symptomatic gallbladder litiasis in all of them. Both operations were carried out using the da Vinci® Surgical Si System in a single docking robotic platform (four robotic arms). Median total surgery time was 145 minutes (Q1-Q3: 115-162). Minimal intraoperative bleeding was recorded (mean 45 ± 15 mL), with no intraoperative complications or conversion. Median length of hospital stay was 3 days (Q1-Q3: 2-4). There were no cases of surgical wound infections or postoperative bleeding documented. Conclusion: Simultaneous robotic-assisted splenectomy and cholecystectomy can be considered safe and feasible interventions in children with hematological diseases that affect both the spleen and the gallbladder. However, further research is needed to enhance the existing evidence and establish a standardized approach.

Vimentin regulates nuclear segmentation in neutrophils.

Granulocytes are indispensable for various immune responses. Unlike other cell types in the body, the nuclei of granulocytes, particularly neutrophils, are heavily segmented into multiple lobes. Although this distinct morphological feature has long been observed, the underlying mechanism remains incompletely characterized. In this study, we utilize cryo-electron tomography to examine the nuclei of mouse neutrophils, revealing the cytoplasmic enrichment of intermediate filaments on the concave regions of the nuclear envelope. Aided by expression profiling and immuno-electron microscopy, we then elucidate that the intermediate-filament protein vimentin is responsible for such perinuclear structures. Of importance, exogenously expressed vimentin in nonimmune cells is sufficient to form cytoplasmic filaments wrapping on the concave nuclear surface. Moreover, genetic deletion of the protein causes a significant reduction of the number of nuclear lobes in neutrophils and eosinophils, mimicking the hematological condition of the Pelger-Huët anomaly. These results have uncovered a new component establishing the nuclear segmentation of granulocytes.

Cerebral venous thrombosis: a practical review.

The evolution of the Coronavirus Disease-2019 pandemic and its vaccination raised more attention to cerebral venous thrombosis (CVT). Although CVT is less prevalent than arterial stroke, it results in larger years of life lost. CVT is more common in women and young patients. Predisposing factors are categorized as transient factors such as pregnancy, puerperium, oral contraceptive pills, trauma, and dehydration; and permanent factors such as neoplastic, vasculitic, thrombophilic, hematologic conditions, infectious causes such as severe acute respiratory syndrome coronavirus-2 infection and HIV. The most common manifestations are headache, seizures, focal neurologic deficits, altered level of consciousness, and cranial nerve palsies. The most common syndromes are stroke-like, raised-intracranial-pressure (ICP), isolated-headache, and encephalopathy, which may have overlaps. Diagnosis is mostly based on computed tomography, magnetic resonance imaging, and their respective venous sequences, supported by blood results abnormalities such as D-dimer elevation. Treatment includes the prevention of propagation of current thrombus with anticoagulation (heparin, or low molecular weight heparinoids and then warfarin, or direct oral anticoagulants), decreasing ICP (even by decompressive craniotomy), and treatment of specific underlying diseases.

Health status and genetic compositions of green turtles (Chelonia mydas) foraging in Brunei Bay.

Long-term monitoring of sea turtle aggregations is critical for understanding the impacts of environmental changes on their population health and habitat suitability. Brunei Bay is a significant foraging ground for green turtles in the South China Sea. We analyzed the body size, hematology and body condition of green turtles for their health status in their foraging ground in Brunei Bay over a period of nine years (2011-2019). Additionally, we used mitochondrial DNA (mtDNA) to evaluate changes in the size and genetic composition of green turtle aggregations. Our findings revealed that the size composition of the green turtle population varied seasonally, but there were no significant temporal changes in genetic and size compositions. Hematology parameters and Fulton's body condition index were consistent with those reported for apparently healthy green turtles. Furthermore, we found that blood reference intervals indicated the turtles were healthy. These results provide valuable baseline data for future comparisons with other foraging aggregations and for long-term monitoring of green turtles in Brunei Bay.

Abstract 14082: Evans Syndrome Post Transcatheter Aortic Valve Replacement: A Rare Presentation

Description of Case: Evans Syndrome is a rare hematologic condition. Here we present a patient who developed Evans Syndrome post TAVR. A 63-year-old male with history of HFrEF and aortic stenosis presented with 2-week history of worsening shortness of breath and bilateral lower extremity swelling. He was found to be in cardiogenic shock. TTE showed (LFLG) aortic stenosis (AS). Due to concomitant cardiogenic shock and tachyarrhythmias, we were unable to perform dobutamine stress echo. A cardiac CT was performed which revealed an aortic valve calcium score of 2761 (Figure 1). The diagnosis of severe AS was confirmed, and patient underwent TAVR. Postprocedural TTE showed significant improvement in EF. Patient’s complete blood count on admission was remarkable for Hgb of 12.5 g/dL and PLT of 148 k/mm 3 . Both Hgb and PLT began to drop significantly following TAVR. We ruled out vascular access site bleeding, mechanical complication from paravalvular leak, nutritional deficiencies, disseminated intravascular coagulation, heparin-induced thrombocytopenia, thrombotic thrombocytopenic purpura, myelodysplastic syndrome, HIV, hepatitis C. Autoimmune hemolytic anemia was identified given elevated lactate dehydrogenase, low haptoglobin, and positive IgG direct antiglobulin test. We started steroids and treat the case as Evans syndrome. PLT count improved from 67 to 117 k/mm 3 within 2 days of steroids initiation. The bone marrow biopsy was deferred to outpatient follow up given the response to steroids. Patient was discharged on oral prednisone. Three-month follow up showed Hgb and PLT with normal limits. Discussion: Anemia and thrombocytopenia are common complications post TAVR. Both anemia and thrombocytopenia are suggested to be excellent markers for clinical outcomes, morbidity and mortality after TAVR. It is crucial to keep a broad differential for post TAVR anemia and thrombocytopenia. Less common causes should be evaluated and addressed to improve prognosis.

Second-Line Therapy Sequencing in Primary Warm Autoimmune Hemolytic Anemia: Splenectomy-Rituximab Versus Rituximab-Splenectomy

Introduction: Primary warm autoimmune hemolytic anemia (wAIHA) is a hematologic condition that affects approximately 1 in 8000 people and occurs when IgG antibodies directed against self-erythrocytes cause hemolysis and exceed the bone marrow's ability to compensate. First-line treatment with glucocorticoids yields sustained remission in less than 30% of individuals. For patients requiring second-line treatment, splenectomy was the preferred treatment for over 50 years, being recommended over rituximab by leading experts as recently as 2010. In the last decade this practice shifted due to concerns of tripartite risk of splenectomy with rates of infection, thrombosis, and perioperative mortality, juxtaposed against the increased experience with rituximab. These risks are outdated as they predate the modern-day vaccination, thromboprophylaxis, and laparoscopic splenectomy era, respectively. Summarily, the 2017 British guidelines dropped splenectomy from second- to third-line for patients with primary wAIHA, consistent with expert opinion in the United States in 2023. Over these same twenty years, the mortality and morbidity of splenectomy has greatly decreased, owing to updated preoperative vaccination standards, prevention of thrombosis, and widespread use of the laparoscopic (i.e., rather than open) technique. Despite these advancements, splenectomy is now used in fewer than 10% of patients with wAIHA. In the absence of a clinical trial randomizing patients to splenectomy versus rituximab, we conducted the first simulation of second-line therapeutic sequencing for adult patients with primary wAIHA with a focus on short-run and long-run effectiveness results. Methods: We constructed a Markov simulation of adult patients with primary wAIHA and requiring second-line therapy to compare the effectiveness of strategy #1: splenectomy followed by rituximab, if necessary, versus strategy #2: rituximab followed by splenectomy, if necessary. Transition probabilities for initial response and time-variant relapse risk with rituximab and with splenectomy were drawn from retrospective primary-wAIHA-specific literature. For rituximab, we assumed that 1) patients maintained in remission for three years following treatment with a rituximab cycle would remain in remission and 2) all patients who relapse more than a year after receiving rituximab, would be retreated with rituximab. Costs were sourced from the Centers for Medicare & Medicaid Services and the Centers for Disease Control and Prevention. Utility values for patients with wAIHA were specific to the reported patient disease status, whether in relapse, partial remission (defined as hemoglobin >10g/dL) or complete remission (defined as hemoglobin >12g/dL). These were sourced from the Global Burden of Disease Study and weighted for the degree of anemia corresponding with each status. Effectiveness was calculated in quality-adjusted life-years (QALYs). The primary outcomes were lifetime discounted costs, QALYs, and net monetary benefits across accepted willingness-to-pay thresholds over short- and long-runs at 5 years and lifetime, respectively. Probabilistic sensitivity analysis was employed to vary all parameters across their uncertainty intervals simultaneously over 10,000 Monte Carlo iterations. Results: In the short-run, strategies #1 and #2 cost $39,700 and $47,100 and accrued 5.21 and 5.26 QALYs (Table 1). In the long run, costs were $909,000 and $912,000 while accruing 22.0 and 22.1 QALYs. Net monetary benefit point estimates were similar across the accepted range of WTP thresholds in both the short- and long-runs. Conclusion: The balance of costs and quality-adjusted life expectancy appears to be comparatively tightly balanced in the sequencing of second-line therapies in primary wAIHA with splenectomy-rituximab versus rituximab-splenectomy. The absence of a clear rituximab-early advantage on a population level may be driven by advancements in vaccination, thromboprophylaxis, and laparoscopic surgical techniques for splenectomy over the last 20 years. Value-of-information analysis would help identify parameters whose uncertainty reduction with future study in the real world would yield a treatment strategy with a definitive advantage. In the meantime, patients whose values and preferences align with splenectomy should not be dissuaded from pursuing it due to perceived risk.

CD34+ Megakaryocytes Associate with Myelodysplastic Syndromes and Related Cytogenetic Abnormalities, but Not Other Hematological Disorders

Background: CD34 is a transmembrane phosphoglycoprotein that is a marker of hematopoietic stem cells and is used clinically to aid in enumeration of blast cells for identification of advanced myeloid neoplasms. Megakaryocytes are differentiated cells from the myeloid lineage that reside in the bone marrow and generally stain negative for CD34 (CD34-). However, CD34 positive (CD34+) megakaryocytes have been observed in hematological disorders such as myelodysplastic syndrome, myeloproliferative neoplasms, and acute leukemias. CD34+ megakaryocytes are proposed to be relatively specific for malignant hematologic conditions and have been reported to associate with a worse prognosis. However, the general clinical, biochemical, and cytogenic characteristics for bone marrow cases of CD34+ megakaryocytes versus CD34- megakaryocytes remains unclear. Objective: We sought to determine the clinical, biochemical, and cytogenetic characteristics associated with finding CD34+ megakaryocytes on bone marrow biopsies. Methods: We identified 281 independent, index bone marrow biopsy cases between 2011-01-01 and 2017-12-31 from Vancouver General Hospital, Canada that underwent CD34 immunohistochemistry at clinical request. The clinical, biochemical, and cytogenetic characteristics of patients were compared based on megakaryocytes being CD34+ vs CD34- on immunohistochemistry. Cases of CD34+ megakaryocytes were defined as having >5% of megakaryocytes staining CD34+, but sensitivity analyses were performed using different percentage cut-offs of 10, 30, and 50%. Results: Out of 281 cases, 134 had CD34+ megakaryocytes (58.2% male sex; mean age = 64.1 years [SD = 15.2 years]) and 147 had CD34- megakaryocytes (57.1% male sex; mean age = 60.0 years [SD = 16.6 years]). There was a significant difference in the distribution of diagnostic categories observed between cases of CD34+ versus CD34- megakaryocytes: myelodysplastic syndromes 35.1% (n=47) versus 21.8% (n=32), acute myeloid leukemias 20.9% (n=28) versus 21.1% (n=31), non-diagnostic etiology 17.9% (n=24) versus 14.3% (n=21), and myeloproliferative neoplasms 10.4% (n=14) versus 19.7% (n=29) (Figure A; Chi-square p-value=0.0004). Sensitivity analyses using different percentage cut-offs to define cases of CD34+ from CD34- megakaryocytes yielded similar results. The differences in biochemical characteristics between cases of CD34+ versus CD34- megakaryocytes were generally unremarkable. The median (IQR) for biochemical parameters between cases of CD34+ and CD34- megakaryocytes were hemoglobin 99 (28) versus 100 (34) g/L, mean corpuscular volume 94 (14) versus 93 (10) fL, neutrophil count 2.20 (3.68) versus 2.46 (3.63) x10 9/L, platelet count 98 (158) versus 112 (194) x10 9/L, and bone marrow blasts 7 (4) versus 3 (14)%. Lastly, there were notable trends in cytogenetic results associated with 90 cases with CD34+ versus 84 cases with CD34- megakaryocytes including: complex karyotypes for 15.6% (n=14) versus 6.0% (n=5), isolated deletion 5q for 7.8% (n=7) versus 1.2% (n=1), and/or isolated trisomy 8 for 5.6% (n=5) versus 2.4% (n=2). Similar cytogenetic results were observed when cases were restricted to only cases of CD34+ versus CD34- megakaryocytes with a diagnosis of myelodysplastic syndrome (Figure B). Conclusion: The presence of CD34+ megakaryocytes is more common in cases of myelodysplastic syndrome relative to other neoplastic hematologic disorders, but does not appear to help with discriminating between neoplastic and non-neoplastic hematological disorders ( e.g. non-diagnostic etiology). Cases with CD34+ megakaryocytes tend to associate with complex karyotype and deletion 5q abnormalities relative to cases with CD34- megakaryocytes.

AK117 (anti-CD47 monoclonal antibody) in Combination with Azacitidine for Newly Diagnosed Higher Risk Myelodysplastic Syndrome (HR-MDS): AK117-103 Phase 1b Results

Background: CD47, an immune checkpoint overexpressed by tumor cells, plays a crucial role in evading the antitumor immune response. AK117, an IgG4 monoclonal antibody (mAb) targeting CD47, has emerged as a potential best-in-class therapy with high affinity binding to CD47 and without inducing hemagglutination effects. By blocking CD47, AK117 effectively triggers macrophage-mediated phagocytosis of hematological malignancy cells, and in combination with azacitidine (AZA), it synergistically enhances the activation of “eat me” signals. In this study, we present the Phase 1b data from the AK117-103 study conducted in patients with newly diagnosed higher risk myelodysplastic syndrome (HR-MDS). Methods: Eligible patients with newly diagnosed intermediate/high/very high-risk MDS, determined by the Revised International Prognostic Scoring System (IPSS-R) prognostic risk score >3, were enrolled to receive combination therapy with AK117 and AZA. AK117 was administered intravenously (IV) following various dosing regimens (20-30 mg/kg once weekly [QW], or 20-45 mg/kg every 2 weeks [Q2W], or 30 mg/kg every 4 weeks [Q4W]), whereas AZA was administered subcutaneously (SC) at the standard dosage (75 mg/m 2, Day 1-7, Q4W). The primary endpoints of this study were safety/tolerability and the complete remission (CR) rate based on the International Working Group (IWG) 2006 response criteria. Results: As of June 9, 2023, 72 patients were enrolled (median age: 66 years, 69.4% males). Most patients exhibited abnormal hematologic conditions at baseline, including decreased hemoglobin, neutrophil count, and platelet count. Specifically, 69.4% of patients had Grade ≥3 anemia, 61.1% had Grade ≥3 neutrophil count decrease, and 47.2% had Grade ≥3 platelet count decrease. For the recommended phase 2 dose (RP2D) group, treated with a combination of AK117 30 mg/kg Q2W and AZA, 30 patients were enrolled with a median age of 67 years, 80.0% of whom were males. According to IPSS-R risk assessment, 33.3%, 23.3%, and 43.3% of patients had intermediate, high, and very high risk, respectively. 30.0% of patients had poor-risk cytogenetics, with 23.0% of those being complex. After a median follow-up of 6.6 months (ranging from 0.4-17.2 months), anemia (a primary adverse event associated with CD47 blocking antibodies) occurred in 30.6% (22/72) of the patients, of which Grade ≥ 3 anemia accounted for 22.2% (16/72). Other commonly observed treatment-emergent adverse events (TEAEs) (≥30%) included decreased neutrophil count (77.8%), decreased white blood cell count (72.2%), decreased platelet count (69.4%), pyrexia (58.3%), decreased lymphocyte count (41.7%), constipation (41.7%), and vomiting (31.9%). Three patients (4.2%) discontinued treatment due to TEAEs. The efficacy of AK117 was compared at different dosages, and ultimately, 30mg/kg Q2W was chosen as the RP2D. As of June 21, 2023, among 27 evaluable patients, the CR rate was 48.1%. 8 patients achieved marrow CR (5 also with hematologic improvement [HI]), and 2 patients achieved HI alone. Among 24 evaluable patients with ≥ 3 months follow-up, the CR rate further escalated to 54.2%. Of 13 evaluable patients who initially required red blood cells (RBC) transfusions, 8(61.5%) became independent of RBC transfusion. Conclusions: AK117 in combination with AZA was well tolerated with low incidence of anemia and demonstrated promising efficacy in patients with newly diagnosed HR-MDS.