Children and adolescents/young adults with relapsed or refractory acute myeloid leukemia (R/R AML) continue to have poor survival rates. In children with R/R AML, prior clinical trials have demonstrated the safety and effectiveness of combining chemotherapy with the BCL2 inhibitor venetoclax and the selective nuclear export inhibitor selinexor. However, even with these developments, some patients remain unresponsive to these combinations.

Preclinical evidence points to a possible synergistic interaction between venetoclax and selinexor, with selinexor possibly overcoming venetoclax resistance. This study aimed to evaluate the toxicity profile and preliminary activity of venetoclax and selinexor with chemotherapy (fludarabine, arabinofuranosyl cytidine, and granulocyte colony-stimulating factor (FLAG)) and report results from the dose escalation phase of the SELCLAX clinical trial.

Study Protocol

Fifteen patients (aged 3–17 years) were enrolled. In dose level 1 (DL1), patients received venetoclax at 360 mg/m2 per dose (max 600 mg) on days 1–21 in combination with selinexor at 40 mg/m2 on days 1, 8, and 15. For dose level 2 (DL2), venetoclax was dosed as in DL1, and selinexor was dosed at 40 mg/m2 and twice weekly on days 1, 3, 8, 10, 15, and 17.

High-Risk Cytomolecular Features 

Almost all of the patients had high-risk cytomolecular features, such as lysine methyltransferase (KMT)2A-rearranged (n=5), nucleoporin (NUP)98-rearranged (n=5), -7/del(7) (n=3), or the oncofusion protein FUS::ERG (n=1).

Complications and Dose-Limiting Toxicity Incidences in Dose Levels 1 and 2

A history of anorexia, mucositis, and poor dentition confounded the one dose-limiting toxicity (DLT) (grade 3 anorexia) that DL1 recorded. One patient at DL2 experienced a hematologic DLT, meaning that their platelet and neutrophil levels were not restored. None of the five other patients in DL2 experienced a DLT, and no significant adverse events were reported.

Treatment Responses and Outcomes

It was observed that 41.7% of patients eligible for evaluation had a complete response or a complete response with incomplete count recovery. A patient at DL2 was deemed unsuitable for DLT evaluation. Following protocol therapy, six patients underwent hematopoietic cell transplantation; five of them are still living.

Source:

Zarnegar-Lumley, S. (2023, December 9). Preliminary Safety and Efficacy of Venetoclax and Selinexor in Combination with Chemotherapy in Pediatric and Young Adult Patients with Relapsed or Refractory Acute Myeloid Leukemia: Selclax. https://ash.confex.com/ash/2023/webprogram/Paper174342.html 

Acute myeloid leukemia (AML) primarily affects older people, who are frequently unable to endure intense chemotherapy due to frailty or comorbid conditions. While venetoclax with azacytidine has a 64% response rate, specific subgroups have some restrictions. Selinexor, particularly when combined with these medications (SAV), appears to hold promise for AML patients with significant comorbidities. 

A prospective trial was designed to analyze the SAV regimen for newly diagnosed (ND) AML patients who are ineligible for intensive therapy to further evaluate its efficacy and safety. This study was presented as a poster at the 65th American Society of Hematology Annual Meeting and Exposition.

Study Protocol 

The study assessed the SAV regimen for elderly AML patients who are not candidates for intense chemotherapy. Selinexor, azacitidine, and venetoclax were given to patients over the age of 75 who had serious comorbidities. Selinexor 60mg on days 3, 10, and 17; azacitidine 75 mg/m2 on days 1–3, 8–9, and 15–16; venetoclax 100mg on day 1, 200mg on day 2, and 400mg on days 3–14. Each treatment cycle was 28 days.

Baseline Characteristics

A total of 20 patients were included in the study from March 2023 until the data cutoff on June 10, 2023, with 16 having de novo or therapy-related AML and 4 having secondary AML with a history of myelodysplastic syndrome. The 20 patients had a median age of 64 years (range: 28–80). The majority had high-risk disease; 12/20 (60%) had intermediate-risk disease, and 8/20 (40%) had adverse-risk disease. 

All patients finished at least one treatment cycle (range: 1–4). The majority were continuing treatment at the time of reporting. Deeper remission potential is possible with prolonged therapy.

 Response Rates After Treatment

The complete response (CR)/CR with incomplete count recovery (CRi) rates and overall response rate (ORR) for all patients, the intermediate-risk group, and the adverse-risk group in the ELN 2022 risk groupings were as follows: 80% (16/20) and 90% (18/20), 75% (9/12) and 91.7% (11/12), and 87.5% (7/8) and 87.5% (7/8), respectively. In comparison, the VIALE-A data revealed a CR/CRi rate of 52.9% for patients at adverse risk, showing a higher remission rate in this research. Three patients were negative for minimal residual disease.

Adverse Events During the Treatment 

Thrombocytopenia (35%), neutropenia (35%), and infections (15%) were recorded as grade 3 or higher adverse events in 10% of patients on the triple regimen. Anemia, nausea, tiredness, anorexia, and hyponatremia were the most frequently reported Grade 1–2 adverse effects. All adverse effects could be treated and improved by adjusting the dose and providing supportive care.

Source
Yang, L. (2023, December 9). Selinexor in Combination with Venetoclax and Azacitidine for Newly Diagnosed (ND) Unfit Acute Myeloid Leukemia (AML): A Multicenter, Open-Label Prospective Study. https://ash.confex.com/ash/2023/webprogram/Paper184581.html 

Although poorly understood, localized intravascular coagulopathy (LIC) is a known consequence of venous malformations (VMs) that can cause thrombosis, bleeding, and the development of phleboliths. Although increases in D-dimer (DD) and decreases in fibrinogen have historically been associated with LIC, no thorough investigations of coagulation markers in VM have been carried out to date.

This study’s goal was to thoroughly describe LIC using data from the Yale Vascular Malformations Program and the Yale Classical Hematology Clinic. This study was presented as a poster at the 65th American Society of Hematology Annual Meeting and Exposition.

 Study Design and Characteristics

 VM patient files (2021–2023) were retrospectively analyzed, and liver iron concentration was determined using coagulation parameters such as von Willebrand factor (VWF), factor VIII (FVIII), alpha-2 antiplasmin (A2AP), plasminogen activator inhibitor-1 (PAI-1), thrombin–antithrombin complex (TAT), D-dimer (DD), fibrinogen, prothrombin time (PT), international normalized ratio (INR), and partial thromboplastin time (PTT). Included in the analysis were 23 patients with VM in total. Most, 82.6%, were female, with a mean age of 38 ± 16 years.

 Prevalence and Site of the Lesion

The most prevalent tissue involvement was in muscle (54.5%), and most patients (59.1%) had a single lesion rather than several. The most common anatomic site was the head and neck (52.2%).

Positive Correlation Between Coagulation Factors

Venous thromboembolism did not affect any patients. Most patients had high TAT levels and normal DD (68.2% and 69.6%, respectively). There was a positive correlation between VWF activity, VWF antigen, FVIII, PAI-1, and fibrinogen. TAT showed an inverse correlation with PT and INR and a positive correlation with PAI-1. Only DD showed a positive correlation with VWF activity. There was poor correlation between TAT and DD; of patients with a normal TAT (n = 7), 85.7% had a normal DD, whereas only 40% of patients with a normal DD (n = 15) had a normal TAT.

Association of Thrombin–Antithrombin Complex and D-Dimer in Different Patients

Two out of three patients (66.7%) with visceral involvement had both high TAT and DD. Three out of four (75%) with skin involvement had a high TAT with normal DD. Nevertheless, these patterns were not statistically significant (P = 0.42 and 0.31, respectively). Of the 11 patients with muscular involvement, 45.5% had normal DD and a high TAT, while 36.3% had both normal DD and a high TAT.

Source

Restrepo, V. (2023, December 9). Comprehensive characterization of coagulation parameters in venous malformations. https://ash.confex.com/ash/2023/webprogram/Paper190609.html 

By stimulating the expression of fetal hemoglobin (HbF), hydroxyurea helps patients with sickle cell disease (SCD). Improved clinical outcomes are correlated with higher HbF levels. The long-term response to the medication, however, varies significantly. The effects of hydroxyurea treatment on the quantitative alterations in hematopoietic stem and progenitor cells (HSPCs) are still poorly understood. 

This study aimed to identify the HSPC profiles linked to hydroxyurea response and ascertain the incidence and clinical significance of decreasing hydroxyurea response in pediatric SCD patients. The study was presented as a poster at the 65th American Society of Hematology Annual Meeting & Exposition.

 Study Design and Characteristics  

Data from 760 pediatric SCD patients at Texas Children’s Hematology Center were retrospectively analyzed (2010–2021). Patients with more than 5 years of hydroxyurea use were chosen. They were classified as sustained response (HbF >20%) or decreased response (HbF <10%) based on each patient’s unique HbF response. The hydroxyurea treatment and clinical data were gathered.

Levels of Fetal Hemoglobin in Children With Sickle Cell Disease

The analysis included 208 children with HbSS or HbSβ0-thalassemia; 148 (71%) showed a sustained response to hydroxyurea, and 60 (29%) showed a decreased response. The hydroxyurea sustained response group subjects had stable values of HbF >20%. In comparison, subjects with a decreased response had a median initial hydroxyurea-induced HbF of 23.9%, which decreased to 9.8% over time (p<0.001). When adjusted for age, these differences persisted. 

Adverse Events During the Treatment  

Patients with a decreased response to hydroxyurea were found to have a significantly higher incidence of clinical complications than those with a sustained response, such as the number of emergency visits (153.3 vs. 120.3 events per 100 patient-years), transfusions (37.4 vs. 11.9), and hospitalizations related to SCD (57.7 vs. 42.0). Vaso-occlusive events requiring admission (27.7 vs. 21.1 events per 100 patient-years), acute chest syndrome (13 vs. 9.9), splenic sequestration (6.4 vs. 3.5), and surgical procedures (7.47 vs. 3.02) were the causes of hospitalizations related to SCD.

Proportions of Hematopoietic Cells

From 40 patient peripheral blood mononuclear cell samples (20 with sustained response, 20 with decreased response), differences emerged: sustained responders showed increased levels of multipotent cells (51.75% vs. 43%), CD49F⁺⁺ HSCs (20.5% vs. 13.55%), and CD235a+/CD71⁺ (11.55% vs. 4.54%) cells. Conversely, decreased responders exhibited increases in percentages of committed megakaryocyte erythroid progenitors and unipotent hematopoietic progenitors (38.55% vs. 52.9%).

Source
Luisanna, S. V. (2023, December 9). Clinical and Hematopoietic Profiles Associated with Sustained Hydroxyurea Response for Patients with Sickle Cell Disease. https://ash.confex.com/ash/2023/webprogram/Paper187335.html 

Damage from hypoxia results in abnormal blood vessel formation in sickle cell disease (SCD), which affects bone marrow and red blood cell production. Erythropoiesis is impeded by a dysfunctional bone marrow environment, which can also harm hematopoietic stem cells (HSCs). The strong polymerization inhibitor GBT021601 raises hemoglobin levels by up to 3 g/dL without causing iron overload or alloimmunization hazards that come with long-term red cell transfusions.

The study investigated the potential of GBT021601 treatment to improve sickle cell disease by restoring bone marrow health, reducing proangiogenic factors, and maintaining hematopoietic stem cell activity. This study was presented as a poster at the 65th American Society of Hematology Annual Meeting and Exposition.

 Study Protocol and Characteristics

Humanized Townes HbSS SCD mice were divided into three cohorts (n = 8 per group: 4 male, 4 female) and fed either standard chow (control) or chow containing 0.1% or 0.2% GBT021601. The mice were phlebotomized and killed after 12 weeks. Spleens were taken and weighed. Centrifugation was used to obtain whole bone marrow from both tibias and one femur; the other was retained for later 3D confocal imaging. Flow cytometry examined the bone marrow for erythroid cell maturation (Annexin V, TER119, and CD44) and HSC markers (Lin, Sca-1, and c-kit). An immunoblot examination of peripheral plasma assessed hypoxia-induced signaling and angiogenesis markers (VCAM-1, VEGF-A, ANG-1, and -2).

Increased Hemoglobin Counts and Reduction of Spleen Size Noted

Hb increased by 3 g/dL on average after GBT021601 administration, and spleen weights decreased significantly (P = 0.0023 and P = 0.0015 for control vs. 0.1% and 0.2%, respectively). Mature red blood cells (RBCs) significantly outnumbered erythroid progenitors at all stages, according to flow cytometry analysis of the removed bone marrow.

 No Significant Changes Observed in Hematopoietic Stem Cells

Dysfunctional bone marrow affects red blood cell production and harms HSCs. Despite GBT021601 treatment, HSC counts showed no notable differences between groups. Further research aims to assess GBT021601’s potential for normalizing bone marrow and protecting edited HSCs.

Changes in Angiogenesis Markers After Administration

VCAM-1 and ANG-1 levels are greater in HbSS mice than in HbAA mice. Treatment with GBT021601 reduced factors leading to pathogenic blood vessel growth. ANG-2 and VEGF-A levels, on the other hand, remained unchanged, with VEGF-A levels being similar between HbSS and HbAA mice.

Source
Hernandez, B. (2023, December 9). Evaluation of GBT021601 as a therapeutic agent to restore bone marrow health and effective erythropoiesis in a sickle mouse model. https://ash.confex.com/ash/2023/webprogram/Paper175022.html 

Biliverdin reductase B (BlvrB) is the fourth-most abundant enzyme in red blood cells (RBCs) and is also present in many other tissues. Existing literature on heme metabolism and bilirubin-related pathologies has predominantly focused on biliverdin reductase A (BlvrA) and the alpha isomers of biliverdin and bilirubin. However, the porphyrin molecule, a crucial component of heme, can generate distinct biliverdin isomers (alpha, beta, gamma, or delta) when subjected to chemically coupled oxidation. 

While BlvrA primarily converts porphyrin to biliverdin-alpha, BlvrB uniquely reduces non-alpha biliverdin isomers to their corresponding bilirubin isomers. Despite being abundantly present and evolutionarily conserved, BlvrB’s function has remained elusive, with its only known impact being a subtle effect on hematopoietic lineage fate. This study, which was shared at the 65th ASH Annual Meeting & Exposition, posited a hypothesis suggesting that BlvrB plays a crucial antioxidant role that becomes particularly important when other redundant antioxidant pathways are limited. 

Biliverdin Reductase B Acts as an Antioxidant in Mature RBCs 

To investigate their hypothesis, the researchers generated a novel BlvrB knockout mouse on a C57BL/6 background. They employed a murine model of primaquine (PQ)-induced oxidative hemolytic anemia in mice deficient in glucose-6-phosphate dehydrogenase (G6PD), representing a clinically relevant scenario with compromised antioxidant biology leading to treatment-limiting pharmacotoxicity in RBCs.

Analysis of Murine Model Confirmed the Hypothesis

The study involved crossing BlvrB-knockout mice with two strains of mice carrying either the A-deficient variant of human G6PD (hG6PD(A-)) or the non-deficient form of human G6PD (hG6PD(ND)). Four distinct mouse strains, including hG6PD(ND) and hG6PD(A-) mice with or without BlvrB deletion, were subjected to either PQ treatment or control PBS injections, with anemia monitored through hematocrit (HCT) and reticulocyte count (RET) analysis. Additionally, high-resolution metabolomics was employed to detect biochemical changes in peripheral blood. 

Results revealed that PQ-induced hemolytic anemia in hG6PD(A-) mice and BlvrB deletion significantly exacerbated this effect through increased oxidation. The mice lacking BlvrB and G6PD(A-) exhibited defective glycolysis, altered redox metabolism, and specific increases in hypoxanthine and sphingosine-1-phosphate (S1P). These findings point to BlvrB’s previously undescribed antioxidant role in RBCs, particularly in the context of oxidative stress induced by G6PD deficiency.

The Bottom Line

In conclusion, the study significantly enhances our understanding of BlvrB’s functional significance, especially in mature RBCs, highlighting its potential as a crucial player in antioxidant defense mechanisms. The observed exacerbation of oxidative injury in the absence of BlvrB suggests its involvement in safeguarding against oxidative stress, emphasizing its relevance to a large population affected by G6PD deficiency. 

Source

Zimring, J. (2023, December 10). Biliverdin reductase B protects against primaquine induced hemolysis – identification of a novel Anti-Oxidant pathway in murine erythrocytes. https://ash.confex.com/ash/2023/webprogram/Paper178655.html 

Human erythroid Krüppel-like factor 1 (EKLF or KLF1) plays an important role in erythroid development. Most patients with KLF1 mutation suffer from severe hemolytic anemia and require regular blood transfusions. These patients also have low pyruvate kinase-red blood cell (PKR) activity.

The study, shared at the proceedings of the 65th ASH Annual Meeting & Exposition, explores the impact of ex vivo mitapivat treatment on the terminal erythropoiesis characteristics of a severe hemolytic anemia patient with KLF1 mutations, aiming to assess parameters such as cell viability, oxidative stress, necrosis, and erythroid differentiation. 

Mitapivat Alleviates Oxidative Stress, Promoting Cell Viability

The patient under investigation, identified with compound heterozygous KLF1 mutations (Q58X, an unusual amino acid; and A298P, a missense mutation), exhibited typical markers of severe hemolytic anemia, including low hemoglobin levels, elevated reticulocyte count, and increased Hb F levels.

The study employed a three-phase primary erythroid culture system, tracking erythroblast transformation, expansion, and differentiation. Throughout the phases, a gradual decrease in erythroblast viability and an increase in intracellular reactive oxygen species (ROS) were observed during erythroid differentiation, indicative of the challenges in terminal erythropoiesis for this patient. Moreover, necrotic cell numbers increased during this process.

Intriguingly, ex vivo treatment with mitapivat mitigated these adverse effects, resulting in decreased intracellular ROS and necrotic cell numbers, ultimately promoting higher cell viability during terminal erythropoiesis.

The study further highlighted the positive influence of mitapivat on stage differentiation in terminal erythropoiesis. The treatment demonstrated a capacity to support effective stage differentiation, as evidenced by favorable changes in stage-specific erythroid markers (glycophoryn A (CD235a) and transferrin receptor (CD71)) compared to untreated differentiated erythroblasts. 

Hence, the findings suggest that ex vivo treatment with mitapivat holds promise for alleviating the challenges associated with terminal erythropoiesis in patients with severe hemolytic anemia due to KLF1 mutations. The observed reduction in oxidative stress, improved cell viability, and enhanced stage differentiation underscore the potential therapeutic value of mitapivat in this context.

The Bottom Line

The study’s outcomes advocate for further exploration and evaluation of mitapivat as a potential treatment option for patients with severe hemolytic anemia due to KLF1 mutations. With ongoing clinical trials exploring mitapivat in various hematological conditions, including PK deficiency, thalassemia, and sickle cell disease, the study adds to the growing body of evidence supporting the drug’s potential efficacy in diverse erythropoietic disorders.

Source

Suksangpleng, T. (2023, December 9). Ex Vivo Treatment By Mitapivat, an Allosteric Pyruvate Kinase Activator, Reduced Oxidative Stress and Promoted Terminal Erythropoiesis in a Severe Hemolytic Anemia Patient Due to Krϋppel-like Factor 1 Mutations. https://ash.confex.com/ash/2023/webprogram/Paper179130.html 

For those diagnosed with sickle cell disease (SCD), allogeneic hematopoietic stem cell transplantation (HCT) and ex vivo autologous gene therapies (GT) are among the most promising treatment approaches. However, a key challenge lies in defining what constitutes a cure, specifically in terms of donor chimerism and functional hemoglobin levels. 

Currently, information on red cell function post-HCT/GT and its correlation with donor chimerism and the resolution of SCD complications is limited. This study, presented at the proceedings of the 65th ASH Annual Meeting & Exposition, aimed to address this gap by providing insights into rheology and whole blood viscosity data in patients with the hemoglobin SS genotype (HbSS) following HCT or GT.

Defining Cure Based on Myeloid Donor Chimerism Is Insufficient

Conducted under IRB-approved protocols at Baylor College of Medicine and Emory University School of Medicine, the study involved the analysis of various parameters, including elongation index (EL) maximum (EI[max]) and minimum and (EI[min]), point of sickling (PoS), hematocrit–viscosity ratio (HVR) at different shear rates (HVR45 and HVR225), and dense red blood cell percentage (DRBC%). These parameters were assessed using a laser-assisted optical rotational red cell analyzer (LORCA) and other validated methods. 

Results from the study, involving 29 patients with a median age of 6.6 years at HCT/GT and a median follow-up of 2.4 years, indicated that while myeloid donor chimerism was generally high (median 94%), the percentage of sickle hemoglobin (HbS%) varied, ranging from 28.9% to 45.2% with HbAS donors and 0% with HbAA donors. Notably, two HbAS HCT patients exhibited myeloid chimerism ≤50%, prompting consideration of the follow-up period and associated parameters. 

The study determined improvements in RBC function over time post-HCT/GT, particularly in patients with HbAA donors, with EI[max] showing a trend toward statistical significance. Patients with HbAS donors displayed significantly higher point of sikcling (PoS) values and a trend toward lower HVR225 compared to HbAA donors.

The study identified a subset of patients (24%) with abnormal red cell function test values post-HCT/GT despite achieving myeloid donor chimerism of >25–30%, a commonly accepted threshold in clinical practice. These findings challenge existing notions and prompt a reconsideration of defining a cure based solely on myeloid donor chimerism.

The Bottom Line

In conclusion, the study advocates for the inclusion of red cell function tests in the follow-up care of HCT/GT patients until values normalize, acknowledging their potential significance in assessing the clinical relevance of these therapeutic interventions. The findings underscore the complexity of defining a cure in the context of SCD and advocate for a comprehensive approach that considers both hematological parameters and functional outcomes.

Source

Patel, A. (2023, December 9). Red Cell Rheology and Blood Viscosity in Pediatric Individuals Having Received Allogenic Hematopoietic Stem Cell Transplantation or Ex Vivo Autologous Gene Therapy for Sickle Cell Disease. https://ash.confex.com/ash/2023/webprogram/Paper188045.html 

Diabetes is one of the most significant health disorders globally, and there has been a fourfold increase in the number of individuals affected by the condition since 1980. Among the various complications associated with diabetes, cardiovascular diseases (CVDs) remain the predominant cause of morbidity and mortality, specifically coronary and artery diseases. Understanding how diabetes affects red blood cells (RBCs) may help lower CVD risk in diabetes patients. In the proceedings of the 65th ASH Annual Meeting & Exposition, researchers shared findings of their in-vitro study investigating the impact of diabetes on RBCs.

Deformed Red Blood Cells in Diabetes Show Higher Occlusion and Adhesion

To comprehensively understand the impact of diabetes on RBC deformability and adhesiveness, two critical factors in assessing disease status and CVD risk, researchers conducted a study employing two proprietary microfluidic assays: the OcclusionChip and Adhesion Biochip. 

The OcclusionChip assay, developed previously, utilizes micropillar arrays with varying spacing, creating a gradient of microcapillaries. These arrays, fabricated through soft lithography, are perfused with isolated RBCs at a constant inlet pressure. Venous samples from diabetic and non-diabetic individuals were collected and tested within 48 hours. Isolated RBCs, resuspended in phosphate-buffered saline, were flown through the chip, and subsequent imaging allowed manual counting of cells trapped within the micropillar arrays, providing the occlusion index as a biomarker for RBC deformability. 

To assess RBC adhesion to endothelial cells, the Adhesion Biochip employed human umbilical vein endothelial cells (HUVECs) cultured within a microfluidic channel under flow conditions. Activated by heme, HUVECs were exposed to isolated RBCs, and adherent erythrocytes were quantified through manual imaging.

Results indicated that RBCs from individuals with diabetes (A1c > 6.5%) exhibited a higher occurrence of occlusion events compared to those from healthy individuals (A1c < 5.7%), signifying a loss of deformability. In contrast, the elongation index, assessed through ektacytometry, showed no statistically significant difference. Moreover, RBCs from diabetic individuals displayed increased adhesion to the endothelium, as evident from the count of adherent RBCs.

The Bottom Line

In summary, the microfluidic assays revealed a substantial adverse impact of diabetes on RBC deformability and adhesiveness. The findings of the study may help create tools that help predict CVD risk in diabetes patients. Hence, there is a need for more extensive studies in the future. It is vital to conduct multi-center studies to confirm and build on these findings. There is a need for studies with larger sample sizes, including healthy individuals, those with pre-diabetes, and those living with various types of diabetes.

Source:

Fraiwan, A. (2023, December 9). Novel RBC adhesion and Deformability assays reveal deleterious effect of diabetes on RBC health. https://ash.confex.com/ash/2023/webprogram/Paper182036.html