British Journal of Haematology

Chimeric antigen receptor (CAR) T‐cell therapy has emerged as a transformative treatment for aggressive B‐cell lymphomas (ABCL), However, about half of patients relapse, most of them early. This study investigates the detection of CAR copies in circulating cell‐free DNA (cfDNA) as a potential predictive biomarker of early relapse (<6 months) to improve patient management. In this research, we have consecutively selected 73 ABCL patients treated with anti‐CD19 CAR T‐cells, analysing CAR levels in peripheral blood and other clinical variables. Our results indicate that no correlation is present between genomic DNA and cfDNA; moreover, higher levels of CAR‐cfDNA on day +14 after infusion (0.44 vs. 0.07; p = 0.019) are associated with improved 6‐month progression‐free survival rates (74.2% vs. 26%. p < 0.01), suggesting that CAR‐cfDNA could be a strong predictor of CAR T‐cell therapy short‐term outcomes. These findings underscore the potential of integrating CAR‐cfDNA analysis into routine clinical practice to enhance the prognostic accuracy and therapeutic strategies for ABCL patients undergoing CAR T‐cell therapy.

Patients with relapsed/refractory (R/R) follicular lymphoma (FL) have limited effective treatment options. Bruton tyrosine kinase inhibitors (BTKis) increase the anti‐tumoural phenotype of tumour‐associated macrophages, providing rationale to combine them with rituximab and lenalidomide (R²). Acalabrutinib, a second‐generation BTKi, has potential to improve R² efficacy without increasing T‐cell–mediated toxicity due to its lack of interleukin‐2–inducible T‐cell kinase inhibition. Here, we report safety and efficacy from a phase 1b dose‐finding study (NCT02180711) evaluating acalabrutinib plus R² in patients with R/R FL. Overall, 29 patients received acalabrutinib plus R² (lenalidomide 15 mg, n = 8; lenalidomide 20 mg, n = 21). At a median acalabrutinib exposure of 21 months, the most common grade ≥3 treatment‐emergent adverse event (TEAE) was neutropenia (37.9%). The incidence of grade ≥3 serious TEAEs was 37.5% and 52.4% in the lenalidomide 15‐mg and 20‐mg cohorts, respectively; overall, the most common were COVID‐19 pneumonia, COVID‐19 infection and pneumonia. Earlier treatment withholdings/reductions were observed in the 20‐mg cohort. With a median follow‐up of 34.1 months, the overall response rate was 75.9%. The complete response rate was 25.0% and 42.9% in the lenalidomide 15‐ and 20‐mg cohorts, respectively. Due to acceptable toxicity and preliminary efficacy, the lenalidomide 20‐mg dose was selected for further investigation.

The subjectivity of morphological assessment and the overlapping pathological features of different subtypes of myeloproliferative neoplasms (MPNs) make accurate diagnosis challenging. To improve the pathological assessment of MPNs, we developed a diagnosis model (fusion model) based on the combination of bone marrow whole‐slide images (deep learning [DL] model) and clinical parameters (clinical model). Thousand and fifty‐one MPN and non‐MPN patients were divided into the training, internal testing and one internal and two external validation cohorts (the combined validation cohort). In the combined validation cohort, fusion model achieved higher areas under curve (AUCs) than clinical or DL model or both for MPNs and subtype identification. Compared with haematopathologists with different experience, clinical model achieved AUC which was comparable to seniors and higher than juniors (p = 0.0208) for polycythaemia vera. The AUCs of fusion model were comparable to seniors and higher than juniors for essential thrombocytosis (p = 0.0141), prefibrotic primary myelofibrosis (p = 0.0085) and overt primary myelofibrosis (p = 0.0330) identification. In conclusion, the performances of our proposed models are equivalent to senior haematopathologists and better than juniors, providing a new perspective on the utilization of DL algorithms in MPN morphological assessment.

The spleen is prone to both physical damage and functional impairment, which can be difficult to detect before catastrophic complications occur. Currently available tests of splenic function are laborious, user‐dependent and unreliable, so there is an unmet need for a reliable test offered routinely in diagnostic laboratories. In this study, we have assessed a simple flow cytometry‐based method measuring high mannose glycans (HMGs) on erythrocytes, which has previously been proposed as a potential test of splenic function. We developed the test as a diagnostic assay using blood from a range of control and potentially hyposplenic samples, including people with sickle cell disease. HMG expression correlated well with manual pit counting, an established method for assessing splenic function (r = 0.6). A threshold of >36% difference compared to the mean of control samples was used to define hyposplenism. At this threshold, the test is 93% sensitive and 100% specific for detecting splenic dysfunction. The test was highly reproducible and stable in blood samples of up to 4 days old. This test is non‐invasive with quantitative data output and requires significantly less operator time than other available techniques, making it a robust new clinical assay for determining splenic function.

Heparin‐induced thrombocytopenia (HIT) is an adverse reaction characterized by anti‐PF4‐heparin antibody generation and hypercoagulability. Imaging flow cytometry (IFC) provides a detailed morphological analysis of platelets, which change upon activation. We evaluated IFC‐derived morphometric features to detect platelet activation and developed a functional assay for HIT diagnosis. We analysed blood samples from 42 patients with suspected HIT and extracted platelet size, shape and texture features using IFC. The morphological features were compared with CD62P expression, light transmission aggregometry (LTA) and a serotonin release assay (SRA) in terms of their ability to predict a HIT diagnosis. Five IFC‐derived morphological features (area, circularity, contrast, diameter and major axis) significantly distinguished resting from activated platelets. The major axis feature performed best for HIT diagnosis, with a sensitivity of 89.3% and a specificity of 92.9% versus functional assays (LTA/SRA); this diagnostic performance was similar to that of CD62P expression on the same platelet donors. The area and diameter had similar specificity (92.9%) and a slightly lower sensitivity (85.7%). The morphological features associated with platelet activation might be effective markers for the diagnosis of HIT, matching platelet CD62P expression assay performance. The high‐throughput IFC exploration of platelet activation offers new perspectives in label‐free analysis and time‐saving.

This study examines the R90 bleeding and platelet disorders gene panel's utility in thrombocytopenia. The study analysed the correlations between the clinical features of patients with thrombocytopenia and genetic outcomes. The diagnostic yield was 46.6% (41/88) for the overall panel for all patients referred locally. Thrombocytopenia >12 months (95% CI = 19.0–191.0, p < 0.01), having a first‐degree relative with thrombocytopenia (16 vs. 7, p < 0.01) and a higher platelet count nadir (67.9 ± 35.0 vs. 39.4 ± 33.9 × 10⁹/L, p < 0.05), were associated with genetic variants, suggesting these as indicators for genetic testing. This supports the R90's role in refining genetic testing criteria in thrombocytopenia.

The age‐associated mutational state of clonal haematopoiesis (CH) is linked to multiple adverse health outcomes. As higher risk CH can lead to progressive neoplastic or vascular disease, there is interest in developing clinical trials to mitigate risk associated with CH. Given the high prevalence of CH, data from clinical trials could have broad public health implications for screening and therapy. Thoughtful consideration is needed to design trials that are both clinically relevant and avoid overmedicalization. Here, we summarize clinical studies of CH to date and provide suggestions and guidance on how to approach designing CH‐focused therapeutic clinical trials. These recommendations are derived from discussions among clinical researchers and scientists emanating from the Inaugural Meeting on Somatic Mutations and Predisease in October 2021.

‘As our understanding of the biology of clonal hematopoiesis expands, a pressing need in the field becomes the design and implementation of clinical trials to help mitigate the risk for progression to overt myeloid neoplasm. Effective clinical trial design will be informed by use of personalized genetic risk to determine eligibility, strategic endpoint selection, and identification of suitable interventions with a goldilocks balance of toxicity and reduced risk of progression. We will only reach this milestone through collaboration’. Commentary on: Haque et al. A blueprint for pursuing therapeutic interventions and early phase clinical trials in clonal haematopoiesis. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19925.

Savin et al. report a retrospective analysis of ABO‐incompatible red cell transfusions in the United Kingdom, France and Germany. In spite of varied strategies for bedside preventative measures, all three countries continue to identify preventable errors leading to ABO‐incompatible red cell transfusions. This report highlights the ongoing challenge of human error as a factor in the persistence of preventable mistransfusions. Commentary on: Savin et al. Frequencies and causes of ABO‐incompatible red cell transfusions in France, Germany and the United Kingdom. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19848.

Non‐transfusional iron overload (IOL) in hereditary spherocytosis (HS) is poorly documented compared with other red blood cell disorders. We studied 13 HS adults with confirmed IOL to identify potential genetic factors. Using a next‐generation sequencing panel of 46 genes related to HS, anaemia and iron metabolism, we found no association between IOL and the genes involved in HS nor the HFE:p.(Cys282Tyr) variant responsible for hereditary haemochromatosis. However, potential genetic factors contributing to IOL were identified in some patients, including variants in HJV (haemojuvelin), SLC40A1 (ferroportin), PKLR (pyruvate kinase), ABCG5 and ABCB8, highlighting the need for larger studies.

Mature B‐cell neoplasms (MBNs) are clonal proliferative diseases encompassing over 40 subtypes. The WHO classification (morphology, immunology, cytogenetics and molecular biology) provides comprehensive diagnostic understandings. However, MBN subtyping relies heavily on the expertise of clinicians and pathologists, and differences in clinical experience can lead to variations in subtyping efficiency and consistency. Additionally, due to the diversity in genetic backgrounds, machine learning (ML) models constructed based on Western populations may not be suitable for Chinese MBN patients. To construct a highly accurate classification model suitable for Chinese MBN patients, we first developed an ML model based on next‐generation sequencing (NGS) from Chinese MBN patients, with an accuracy of 0.719, which decreased to 0.707 after model feature selection. Another ML model based on NGS and tumour cell size had an accuracy of 0.715, which increased to 0.763 after model feature selection. Both models were more accurate than models constructed using Western MBN patient databases. Furthermore, by adding flow cytometry for CD5 and CD10, the accuracy reached 0.864, which further improved to 0.872 after model feature selection. These models are accessible via an open‐access website. Overall, ML models incorporating multiplatform tests can serve as practical auxiliary tools for MBN subtype classification.

Alloimmunization to minor red blood cell antigens has been linked to patient morbidity and mortality, especially among people living with sickle cell disease and transfusion‐dependent thalassaemia. Prophylactic antigen matching is commonly used to prevent alloimmunization, but the evidence supporting this common practice is very limited. The report by Wolf et al. summarizes the latest literature on this topic and importantly finds that there is insufficient evidence to recommend prophylactic extended antigen matching (beyond ABO, RhD, RhCcEe and K). In an era of chronic blood shortages, this approach may help to assure patient access to elective surgery and cellular therapies, while preserving the supply of extensively antigen‐matched red cells for patients with specific needs. Commentary on: Wolf et al. Red cell specifications for blood group matching in patients with haemoglobinopathies: An updated systematic review and clinical practice guideline from the International Collaboration for Transfusion Medicine Guidelines. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19837

For patients with acute myeloid leukaemia (AML) who achieve complete remission (CR) after induction therapy, subsequent allogeneic haematopoietic stem cell transplantation (allo‐HSCT) reduces the risk of relapse. However, not all patients are eligible, warranting effective alternative maintenance strategies. Oral azacitidine is the only non‐targeted therapy approved by both the United States (US) Food and Drug Administration and the European Medicines Agency for the maintenance or continued treatment of allo‐HSCT‐ineligible patients with AML achieving CR or CR with incomplete haematological recovery following induction chemotherapy. Midostaurin and histamine dihydrochloride are approved in Europe as maintenance therapy for AML in remission, and quizartinib is approved in the United States and Europe for the treatment and maintenance of patients with newly diagnosed FLT3‐ITD AML. Barriers to maintenance treatment include limited clinical trial data informing appropriate patient and treatment selection, patient preference, financial burden and paucity of real‐world data. This article discusses current maintenance treatment guidelines for patients with AML in remission but not proceeding to allo‐HSCT and reviews clinical trial data for agents approved for use in remission. Ongoing studies of interest and considerations for future efforts are also discussed.

CAR‐NK cell therapy is an emerging immunotherapy for cancer. Recent advancements in genetic engineering have improved their antitumour efficacy through strategies such as dual‐targeting CARs, cytokine armouring and logic gating to minimize fratricide and off‐target effects. Gene‐editing approaches, including checkpoint deletion and overexpression of key effector molecules, further enhance their persistence and cytotoxicity. Additionally, the availability of diverse NK cell sources, such as peripheral blood, umbilical cord blood, CD34⁺ haematopoietic stem and progenitor cells, and iPSCs, offers scalability and flexibility for clinical applications. These innovations position CAR‐NK cells as a versatile and potent therapeutic platform for treatment‐resistant malignancies. image

Cancer patients with haematological malignancies are at risk for chronic hepatitis E virus infection following chimeric antigen receptor (CAR) T‐cell therapy. Strong clinical suspicion is essential for the early diagnosis and prompt treatment of this difficult‐to‐treat type of viral hepatitis. Commentary on: Schwarz et al. Chronic hepatitis E in a patient after CAR‐T cell treatment for diffuse large B‐cell lymphoma and rapid progression towards decompensated liver cirrhosis. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19892.

In 2014, the International Myeloma Working Group (IMWG) updated the criteria for diagnosing myeloma and added three additional criteria to the traditional Calcium elevation, Renal impairment, Anemia, Bone disease (CRAB) criteria, called the Sixty % marrow plama cells, Light chain ratio >60, Mri demonstates lytic lesions (SLiM) criteria (clonal bone marrow plasma cells ≥60%, involved to uninvolved free light chain ratio (FLCr) ≥100 and >1 focal lesion on magnetic resonance imaging (MRI)). We report on the outcomes of 30 patients who underwent autologous stem cell transplantation (ASCT) where therapy was initiated solely based on SLiM criteria and compared them to a matched cohort of 60 patients whose myeloma‐defining event was CRAB. The SLiM cohort had a shorter median time to neutrophil (15 vs. 16 days, p = 0.049) and platelet (15 vs. 17 days, p = 0.0004) engraftment. The 36‐month overall survival (OS) was 100% in the SLiM group and 93.27% in the control group (95% CI 83.06%–97.42%), with a trend towards longer OS in the SLiM cohort (p = 0.065). The 36‐month progression‐free survival (PFS) was 91.61% in the SLiM (95% CI 69.93%–97.87%) and 65.95% in the control group (95% CI 52.31%–76.53%). There was no difference in the PFS between the cohorts (p = 0.414). ASCT is efficacious and safe in MM patients transplanted only due to SLIM criteria. Early intervention in this asymptomatic cohort did not appear to result in deeper responses or better PFS compared to outcomes in symptomatic patients.

HIF‐2α, encoded by EPAS1, plays a dominant role in regulating erythropoietin (EPO) production, maintaining the dynamic balance of erythropoiesis. Gain‐of‐function mutations in EPAS1 cause erythrocytosis. However, anaemia caused by EPAS1 loss‐of‐function mutations has been confined to only one case report, and the underlying mechanism remains unclear. Herein, the reanalysis of high‐throughput sequencing data from 311 patients with anaemia identified three monoallelic EPAS1 variants from three unrelated families in a paediatric anaemia cohort. The probands showed highly consistent clinical phenotypes with normocytic and normochromic anaemia, reticulocytopenia and relative deficiency of serum EPO, characterised as congenital hypoplastic anaemia. In vitro studies suggested that defects in steady‐state protein abundance, nuclear localisation and binding with co‐activator in EPAS1 variants lead to impaired EPO transcriptional activation. Therefore, loss‐of‐function mutations in EPAS1 can cause erythroid hypoplasia in an EPO‐dependent manner. This study identified a new causative gene for congenital hypoplastic anaemia and clarified the molecular aetiology of loss‐of‐function EPAS1 mutations.

An inclusive clinical trial ecosystem is essential to obtain scientific results that can be generalized to a broad patient population. When possible, all efforts should be made to remove geographic, demographic, cultural and ethnic barriers for enrolment in clinical trials. However, to do this effectively, we need more knowledge about factors influencing clinical trial participation and practical frameworks to enhance diversity in clinical trials. Commentary on: Jones et al. Inequalities in geographic barriers and patient representation in lymphoma clinical trials across England. Br J Haematol 2024 (Online ahead of print). doi: 10.1111/bjh.19907.

The distribution of trial site locations may lead to disparities in geographic access and affect patient representativeness in clinical trials. We utilised trial data covering 1993–2022 from the National Institute for Health and Care Research (NIHR) Open Data Platform, 2011 and 2021 English Census and geographic data and English individual‐patient cancer registry data for patients diagnosed with lymphoma between 1997 and 2017. To assess representation, we compared patient age and sex between trial participants and the incident population. We mapped the distance and travel times of English lower layer super output areas (LSOAs) to their nearest research active NHS Trusts and assessed associations between distance and travel times and the geographic and sociodemographic characteristics of the LSOAs. Trial participants were younger than the incident population and more likely to be male. The closest NHS Trust to more than half of English LSOAs was not research active. Greater LSOA mean age, male percent, White British percent, rurality and coastal/border status were positively associated with distance and travel time (at prespecified p < 0.05 level), while greater deprivation was negatively associated. Female and older lymphoma patients in England are underrepresented in trials, with the latter facing a higher burden of geographic barriers.

Traditionally, patients with asymptomatic, advanced‐stage follicular lymphoma were managed with a watchful‐waiting approach until disease progression. The ‘Watch and Wait’ Phase‐3 randomised international trial examined whether rituximab could delay the need for treatment and the effect on quality of life (QoL). In this article, we present the long‐term results of the QoL aspect of the trial. Patients were randomised to watchful‐waiting (Arm A), rituximab induction (Arm B) or rituximab induction followed by maintenance (Arm C). We present the QoL outcomes from 180 patients (Arm A), 188 patients (Arm C) and an exploratory analysis of 82 (Arm B) compared to 81 and 84 patients concurrently randomised to arms A and C. Arm C reported greater improvement in emotional well‐being overtime (Month 37, p = 0.0078) and were significantly more likely to feel in control of their situation than watchful‐waiting patients (Month 25, p = 0.0004; Month 37, p = 0.0476). Watchful‐waiting patients were significantly more likely to avoid thinking about their illness, did not find learning about their illness helped them and were more likely to attach unpleasant connotations to clinic visits (Month 7, p = 0.0032; Month 13, p = 0.0015; Month 25, p = 0.0104). These results demonstrate improved QoL scores in the induction and maintenance rituximab arm, indicating that rituximab was not detrimental to QoL and resulted in an improved QoL in some domains.

Navigating choice of JAK inhibitor (JAKi) therapy for patients with myelofibrosis who are JAKi‐naïve and for those who have previously been treated with a JAKi. image