ABSTRACT:T-cell acute lymphoblastic leukemia (T-ALL) results from the malignant transformation of thymocytes blocked in their differentiation. Surface expression of the γδ T-cell receptor (γδTCR) is surprisingly frequent in T-ALLs, questioning the susceptibility of the γδ-lineage to leukemogenesis. Among 1233 T-ALLs phenotyped in our center, 33% (n = 403) expressed a TCR, of which 47% (n = 191; 113 adults, 78 children) were positive for γδTCR (γδTCR+). Using a comprehensive analysis, we were able to delineate 2 distinct γδTCR+ T-ALL subtypes, with distinct physiological counterparts. The first (75% of cases) was characterized by ectopic expression of homeodomain-containing oncogenes (HD+), Vβ-Jβ rearrangements, and phenotypic (including surface pre-TCRα chain) and transcriptional profiles reminiscent of cortical thymocytes and was, therefore, termed cortical-like γδ T-ALLs. Transduction of murine T-cell progenitors and human CD34+ cells with HOXA9 or TLX3 (HD+ oncogenes) led to a differentiation bias toward γδTCR-expressing thymocytes. The second subtype (25%) exhibited phenotypic and transcriptional profiles reminiscent of γδ thymocytes, and was termed bona fide γδ T-ALLs. These findings were validated in the COGAALL0434 cohort. Although bona fide γδ T-ALLs were enriched for early T-cell progenitor (ETP)-like and KMT2A-rearranged cases, they mostly eluded the phenotypic definition of ETP-ALLs. Similar to the ETP-like subtype, bona fide γδ T-ALLs were associated with a poor initial response to chemotherapy but were sensitive to the BCL2 inhibitor venetoclax. Our results reveal developmental heterogeneity behind γδTCR expression in T-ALLs and suggest that overrepresentation of this subtype reflects αβ-lineage commitment repression by HD+ oncogenes. These trials were registered at www.clinicaltrials.gov as NCT00222027 (GRAALL2003), NCT00327678 (GRAALL2005), NCT03709719 (GRAALL2014), and NCT00408005 (Children's Oncology Group AALL0434 trial).

Introduction: Immunochemotherapy remains the cornerstone of treatment for Mantle Cell Lymphoma (MCL). However, 25% of patients experience early progression, with survival rates of less than two years. Current prognostic tools, such as the MCL International Prognostic Index (MIPI), and poor prognostic histological and genetic features are insufficient for stratifying patients into individualized therapeutic strategies. This study aimed to identify biomarkers for high-risk MCL patients using an integrated analysis of clinical and biological factors. Methods: We analyzed data from 299 patients enrolled in the LyMa phase 3 trial, with a focus on high-risk patients, defined by refractoriness to immunochemotherapy or relapse within 12 months post-autologous stem cell transplantation. We used optical genome mapping (OGM) on frozen samples, alongside whole-exome sequencing (WES), RNA sequencing, and DNA methylation arrays analyses on FFPE tumor biopsies to identify genetic, transcriptomic and epigenetic alterations. Machine learning models, including random forest analysis and Partial Least-Squares Discriminant Analysis (PLS-DA), were employed to predict high-risk MCL status. Results: Among the 299 patients, 31 (10.4%) were identified as high-risk (HR) with a median overall survival of 8.5 months after relapse. HR patients exhibited significantly higher levels of LDH, higher-risk MIPI scores (45% vs. 16%, p<0.001), Ki-67 >30% (71% vs. 31%, p<0.001) and blastoid/pleomorphic histology (32% vs. 9%, p<0.001). In multivariate analysis, only high-risk MIPI score, and Ki-67 >30% were associated with HR MCL. These factors were insufficient to specifically capture HR patients, as one-third of long-term responders would have been misidentified as high-risk. The high-risk (HR) subgroup displayed a greater burden of complex genetic alterations, with significantly increased frequencies of TP53 alterations (OR 25.4, p < 0.001), CDKN2A deletions (OR 4.5, p = 0.015), RB1 deletions (OR 4.9, p = 0.024), MYC gains (OR 5.8, p = 0.047), and MIR17HG gains (OR 11.8, p = 0.013). To improve predictive accuracy, an integrative analysis combining well-established prognostic markers with gene alterations assessed by WES, was performed. Random forest analysis achieved a test accuracy of 91% when predicting HR MCL status, with a ROC AUC of 96%. The sensitivity was 84% and the specificity was 96%, with a misclassification rate of 14%. The most influential features included the Ki-67 index, histological subtype, TP53 alterations, MIPI score, and gains of MYC and MIR17HG. Unsupervised Uniform Manifold Approximation and Projection (UMAP) analysis of gene expression profiling on 49 FFPE samples, including 15 HR MCLs, showed that HR MCLs tended to cluster together, but the distinction was not perfect. Supervised analyses, using PLS-DA, indicated potential overfitting, suggesting that transcriptomic signals alone are insufficient for perfect discrimination. In contrast, DNA methylation analysis of 29 FFPE samples, including 12 HR MCLs, revealed a distinct epigenetic signature that robustly discriminated HR MCLs from control cases. Supervised approaches (PLS-DA) identified differentially methylated probes (DMPs, n=225) that perfectly discriminated HR MCL from controls. Importantly, this epigenetic signature was validated in an independent cohort (Barcelona cohort, n=64). To explore the genome-wide impact of DNA methylation on gene expression, we performed correlation analyses between promoter methylation and transcriptomic data across all protein-coding genes. A subset of genes showed significant correlations, with a predominant inverse relationship in HR cases, absent in controls, indicating that promoter hypermethylation may drive transcriptional deregulation in this subgroup. Notably, CHL1, a tumor suppressor, and KLHL6, associated with chemoresistance, demonstrated strong inverse correlations between methylation and expression, supporting their involvement in HR MCL pathogenesis. Conclusion: This study provides an integrated characterization of high-risk MCL, identifying a novel epigenetic signature that outperform traditional prognostic markers. Our baseline epigenetic approach may enhance patient stratification and support the development of personalized therapies. These results support the combined analysis of genetic and epigenetic features to capture MCL's full biological complexity.

Refractory and/or relapsing T-cell acute lymphoblastic leukemia (T-ALL) remains a major therapeutic challenge. The pre-T-cell receptor (TCR) pathway has recently emerged as a therapeutic target via LCK inhibition in this context. However, there is a need for simple and quickly assessable biomarkers to predict sensitivity to LCK inhibitors. Moreover, targeting LCK alone by tyrosine kinase inhibitors, such as dasatinib, often results in transient clinical responses, emphasizing the need for efficient combination strategies. Here, we assessed pre-TCR alpha chain (pT alpha) surface expression by flow cytometry in a unique series of 50 adult T-ALL patient-derived xenografts (PDXs). We show that cases displaying a cortical phenotype often express high levels of surface pT alpha (pre-TCR+ T-ALL) and that the latter associates with LCK activation. Furthermore, we show that ectopic interleukin-7 receptor (IL-7R) expression can rescue pre-TCR+ T-ALL from dasatinib cytotoxicity (5 PDXs). We tested whether coinhibition of pre-TCR and IL-7R signaling pathways could be synergetic in pre-TCR+ IL-7R(+) T-ALL (11 PDXs). Combination of JAK inhibitors, ruxolitinib or tofacitinib, with dasatinib elicited strong and specific synergy in IL-7R(+) pre-TCR+ T-ALL in vitro, including in the relapse setting (4 of 28 patient-derived primary samples). Using 3 adult-PDX models, we show that in vivo treatment with this combination significantly delayed leukemic progression and prolonged survival compared with either monotherapy. This preclinical study thus proposes the use of pT alpha as a biomarker of LCK-inhibitor sensitivity in T-ALL, and suggests that dual targeting of IL-7R and pre-TCR signaling pathways may be a relevant therapeutic strategy in a substantial proportion of adult T-ALL.

T‐cell acute lymphoblastic leukemia (T‐ALL) is a rare and aggressive hematological malignancy primarily affecting adolescents and young adults and is scarce in infants and toddlers under age 3. Unlike B‐ALL, T‐ALL in this young population remains poorly characterized due to limited data and lacks evidence‐based guidelines to help clinicians determine the optimal treatment approach. In this study, we conducted a comprehensive genetic analysis of infant/toddler T‐ALL cases from a French national cohort, utilizing high‐throughput targeted sequencing, optical genome mapping, and RNA sequencing. Genetic analysis revealed the absence of TLX1/3 dysregulation. Instead, we identified a significant prevalence of NKX2 rearrangements ( n = 9, 33%), co‐occurring with MYB alterations ( n = 5/9) or chromothripsis‐like events ( n = 3/9). Additional findings included TAL1/‐like anomalies (30%), STAG2::LMO2 (15%), ETS rearrangements (15%), and rarely, KMT2A rearrangements (7%). Comparative analyses with 245 patients aged 3–18 years, enrolled in the pediatric FRALLE2000T French protocol, underscored the distinct clinical and genetic profiles of infants/toddlers. Despite presenting with higher rates of hyperleukocytosis and slower responses to treatment, they demonstrated comparable survival outcomes to older pediatric patients, with a 5‐year overall survival (OS) rate of 75.4% (95% confidence interval [CI]: 60.0%–94.8%) versus 75.2% (95% CI: 69.8%–81.1%), p = 0.86. Notably, alterations in NKX2 , KMT2A , and STAG2::LMO2 delineated oncogenic subgroups exhibiting a remarkable 100% OS rate, while patients with TAL1 or ETS dysregulation experienced less favorable outcomes. This was further supported by analyses of data from the COG AALL0434 trial, enhancing our understanding of T‐ALL in infants/toddlers. Large‐scale collaborative studies remain essential to confirm these findings and refine treatment strategies.

TAL1 is one of the most frequently dysregulated oncogenes in T-cell Acute Lymphoblastic Leukaemia (T-ALL). However, the precise frequency and prognostic impact associated with its dysregulation remains unclear and is confounded by TAL1’s diverse dysregulation mechanisms. TAL1 dysregulation is detected by TAL1 transcript quantification, though this technique may be subject to interference by TAL1 transcripts deriving from residual haematological cells that physiologically express high levels of the gene. We hypothesised TAL1 DNA methylation could provide a more reliable biomarker than TAL1 transcript quantification alone. We extensively studied TAL1 dysregulation in a large adult and paediatric T-ALL cohort (n = 401) and designed a TAL1 specific MS-MLPA assay to determine methylation levels. Whereas monoallelic TAL1 + T-ALL had homogeneous gene expression profiles, never expressed other driver oncogenes and were TAL1 hypomethylated (methylation ratio <0.4), biallelic TAL1 + T-ALL were enriched in expression of other driver oncogenes (TLX1, TLX3, HOXA), and had heterogeneous transcriptomes and TAL1 methylation levels. In PDX analysis, monoallelic TAL1 expression was stable, contrary to biallelic expression which mostly derived from residual non-malignant haematopoietic cells. Importantly, we report 5 novel TAL1 dysregulation mechanisms using long-read nanopore and OGM analysis, and show that TAL1 hypomethylation identifies TAL1 dysregulation, and is associated with worse prognosis.

In mantle cell lymphoma, early progression of disease has been associated with short overall survival. The impact of clinical, pathological, and treatment strategies on the risk of early relapse has not been assessed in a large cohort of patients. We performed a pooled analysis of patients recruited in France from six randomized first-line MCL trials. Among 1386 treated MCL patients, 1280 were evaluable for POD24 status: 299 (23.4%) with a POD24 event and 981 (76.6%) without. Patients with a POD24 event had a median OS of 9.3 months (95% CI 8.4-11.8) versus not reached (95% CI 97.8-NR) for those without POD24 events. The median post-relapse OS of patients with a late relapse was also significantly longer at 49.4 months (HR = 0.39; 95% CI 0.31-0.48; P < 0.001) as compared to POD24 patients. Baseline variables (age, performance status, B symptoms, LDH/ULN, leukocytes, blastoid variant, and Ki-67 > 30%) were significantly associated with the risk of POD24, independent of ASCT. Among responding patients at end-of-induction (n = 1105) who had received ASCT, anti-CD20 maintenance was associated with a decreased risk of POD24 (OR = 0.37; 95% CI 0.1-1.0). Using this large data set of patients in clinical trials, we confirm that POD24 status is strongly associated with subsequent OS in MCL. Rituximab maintenance provided significant protection against the risk of POD24, independent of ASCT. Progression within 2 years should be considered as a primary endpoint in future studies.

PURPOSE Minimal residual disease (MRD) can predict outcomes in patients with mantle cell lymphoma (MCL) but data are limited for younger patients undergoing ASCT (autologous-stem-cell-transplantation) and rituximab maintenance (RM) and no data are available on the clinical value of combining MRD with positron-emission-tomography (PET). PATIENTS AND METHODS. Long term follow-up data from a phase III trial in newly-diagnosed MCL patients of < 66 years (LYMA; NCI NCT00921414, Sarkozy C et al, J Clin Oncol, 2023) were examined to determine the relationship between MRD, PET and progression-free survival (PFS), overall survival (OS) and progression-of-disease before 24 months (POD24). Pre- and post-ASCT timepoints were considered and analyses were conducted in both the RM and observation (Obs) arms. MRD was evaluated by quantitative polymerase chain reaction (qPCR; minimal sensitivity 10-4) of clonal immunoglobulin gene rearrangements, in peripheral blood (PB) and / or bone marrow (BM). MRD status was interpreted according to EURO-MRD guidelines. RESULTS: MRD assays were established in 223 of 299 enrolled patients (74.6%). The MRD patient set was broadly similar to the non-MRD set except for a higher incidence of bone marrow involvement and Ann Arbor stage II/III patients in the former. Non-evaluable MRD was mostly due to no diagnostic or follow-up samples, no MRD target or MRD assay failure. Overall, MRD measured in either PB and / or BM was negative in 123/195 patients (63%), pre-ASCT, and 155/192 patients (81%), post-ASCT. MRD negativity rates were higher in PB at pre-ASCT (77%, 144 of 187 MRD-evaluable patients) and post-ASCT (94%, 181/193 patients) compared to BM at either time-point [pre-ASCT: 64% BM-MRD negative, 115/180 patients; post-ASCT: 81% BM-MRD negative, 137/170 patients]. Pre-ASCT MRD status in PB (but not BM), was predictive of PFS (hazard ratio [HR]: 2.43 [95% CI, 1.53 to 3.86]; P=0.0001), OS (HR, 3.31 [95% CI, 1.87 to 5.85]; P<0.0001) and POD24 (OR, 5.41 [95% CI, 2.15 to 13.64]; P=0.0003). Post-ASCT, PB-MRD status (but not BM-MRD) was predictive of PFS (HR, 2.24 [95% CI, 1.01 to 4.95]; P=0.0414) (but not OS or POD24). When analyzed by treatment arm, patients in RM who were PB-MRD negative at pre-ASCT showed longer PFS and OS compared to those who were PB-MRD positive (HR, 2.86 [95% CI, 1.10 to 7.44]; P=0.0241 and HR, 2.94 [95% CI, 1.03 to 8.38]; 0.0361, respectively). Patients in the observation arm who were PB-MRD positive at pre-ASCT fared poorly when compared to patients who were PB-MRD negative with a shorter PFS (HR, 2.45 [95% CI, 1.24 to 4.83]; P=0.0079) and OS (HR, 3.96 [95% CI, 1.36 to 11.54]; P=0.0066). Insufficient events were available for post-ASCT analyses. However, RM provided superior PFS (HR, 0.44 [95% CI, 0.21 to 0.89]; P=0.0186) (but not OS) for PB-MRD-negative patients at pre-ASCT, while at post-ASCT, PB-MRD negative patients under RM showed improved PFS (HR, 0.32 [95% CI, 0.16 to 0.62]; P=0.001) and OS (HR, 0.45 [95% CI, 0.22 to 0.92]; P=0.0243). In view of the stronger predictive power of PB-MRD, over BM-MRD, we next asked whether integration of PET and MRD could improve outcome prediction. Superior outcome was associated to negativity for both PB-MRD and PET at either pre-ASCT (108/171 of patients with available PET/MRD data, 63%: PFS (HR, 2.14 [95% CI, 1.34 to 3.41]; P=0.0011), OS (HR, 2.195 [95% CI, 1.195 to 4.034]; P=0.0095), POD24 (OR, 2.98 [1.17-7.62]; P=0.0223) or post-ASCT (120/147 patients with available PET/MRD data, 81.6%: PFS (HR, 2.4 [95% CI, 1.28 to 4.50]; P=0.0048) or OS (HR, 3.02 [95% CI, 1.40 to 6.52]; P=0.0032) compared to PB-MRD and / or PET positive patients at either timepoint. When analyzed by treatment arm (RM or Obs), PET/PB-MRD status at pre- or post-ASCT did not impact outcome. However, RM maintained impact on PFS (but not OS) in post-ASCT (but not pre-ASCT), double-negative PB-MRD/PET patients (HR, 0.32 [95% CI, 0.14 to 0.69]; P=0.0025). CONCLUSION: Early sequential PB-MRD monitoring at the pre- and post-ASCT treatment phase is a powerful strategy for early clinical outcome prediction in MCL in the ASCT RM setting and has potential as a surrogate endpoint for clinical trials. Our results do not support de-escalation of RM upon MRD/PET negativity either pre- or post-ASCT. Combining MRD with PET offers improved predictive power and warrants evaluation as a new platform for response-adapted treatment in MCL in a constantly changing therapeutic environment.

The ultimate goal of value-based laboratory medicine is maximizing the effectiveness of laboratory tests in improving patient outcomes, optimizing resources and minimizing unnecessary costs. This approach abandons the oversimplified notion of test volume and cost, in favor of emphasizing the clinical utility and quality of diagnostic tests in the clinical decision-making. Several key elements characterize value-based laboratory medicine, which can be summarized in some basic concepts, such as organization of in vitro diagnostics (including appropriateness, integrated diagnostics, networking, remote patient monitoring, disruptive innovations), translation of laboratory data into clinical information and measurable outcomes, sustainability, reimbursement, ethics (e.g., patient empowerment and safety, data protection, analysis of big data, scientific publishing). Education and training are also crucial, along with considerations for the future of the profession, which will be largely influenced by advances in automation, information technology, artificial intelligence, and regulations concerning in vitro diagnostics. This collective opinion paper, composed of summaries from presentations given at the two-day European Federation of Laboratory Medicine (EFLM) Strategic Conference "A vision to the future: value-based laboratory medicine" (Padova, Italy; September 23-24, 2024), aims to provide a comprehensive overview of value-based laboratory medicine, projecting the profession into a more clinically effective and sustainable future.

Obinutuzumab (O) and rituximab (R) are 2 CD antibodies that have never been compared in a prospective randomized trial of mantle cell lymphoma (MCL). Herein, we report the long-term outcome of the LyMa-101 trial, in which newly diagnosed patients with MCL were treated with chemotherapy plus O before transplantation, followed by O maintenance (O group). We then compared these patients with those treated with the same treatment design with R instead of O (R group). A propensity score matching (PSM) was used to compare the 2 populations (O vs R groups) in terms of measurable residual disease (MRD) at the end of induction (EOI), progression-free survival (PFS), and overall survival (OS). In LyMa-101, the estimated 5-year PFS and OS after inclusion (n = 85) were 83.4% (95% confidence fi dence interval [CI], 73.5-89.8) and 86.9% (95% CI, 77.6-92.5), respectively. At EOI, patients treated in the O group had more frequent bone marrow MRD negativity than those treated in the R group (83.1% vs 63.4%; chi 2 , P = .007). PSM resulted in 2 sets of 82 patients with comparable characteristics at inclusion. From treatment initiation, the O group had a longer estimated 5-year PFS (P P = .029; 82.8% vs 66.6%; hazard ratio [HR], 1.99; 95% confidence fi dence interval (CI), 1.053.76) and OS (P P = .039; 86.4% vs 71.4%; HR, 2.08; 95% CI, 1.01-4.16) compared with the R group. Causes of death were comparable in the 2 groups, the most common cause being lymphoma. O before transplantation and in maintenance provides better disease control and enhances PFS and OS compared with R in transplant-eligible patients with MCL. These trials were registered at www.clinicaltrials.gov as #NCT00921414 and NCT02896582.

Phenotypic, transcriptomic and genetic validation of PDX models

Introduction Around 5-10% of mantle cell lymphoma (MCL) patients are primary refractory to chemotherapy. They have an extremely dismal prognosis, as do responsive patients that relapsed within 12 months. Despite better understanding of risk factors and evolving classifications, these scores do not predict all high-risk patients and were not designed to guide treatment strategy in newly diagnosed MCL. Optical genome mapping (OGM) is a cutting-edge technology developed for genome-wide detection of structural variants (SVs) including balanced and unbalanced translocations, inversions, insertions, deletions, duplications as well as copy number variations (CNVs). Methods High-risk (HR) patients included in the prospective phase III LyMa trial (NCI NCT00921414; Le Gouill et al. NEJM 2017), were identified as patients experiencing early progression of disease (i.e. within 1 year after randomization). We performed OGM in the HR cohort using available frozen tumoral tissue. Low-risk patients (LR) were used as a control. The data were analyzed with the Bionano Solve software. Results Among 299 MCL patients included in the LyMa trial, 31 high-risk MCL patients were identified (10.4%). OGM was performed in 15 patients: 8 HR and 7 LR. OGM successfully detected the t(11;14) in all patients. We detected a median of 38 SVs (range, 16-129) and 12 CNVs (range, 1-119) per case, higher in HR patients than in LR patients (median 51 vs. 32, p=0.07 for SVs; and 14 vs. 5, p=0.11 for CNVs). Chromothripsis and chromoplexia occurred in both cohorts, but breakage-fusion-bridge (BFB) cycles was only observed in 2 HR MCL. HR MCL were characterized by frequent loss of 17p/ TP53 (63% vs. 0%, p=0.03), and rare deletions of 11q22-q23/ ATM (13% vs. 57%, p=0.12). Three HR patients had no TP53 deletions, two of whom presented a gain of BCL2. Gain of UBR5, that influence transcription and posttranscription processes, was found in 3/8 HR patients compared to 1/8 LR patients. MTAP deletion that has been recently described as biomarkers predicting refractory MCL was found in 5/8 HR MCL and is associated with CDKN2A/2B deletions, compared to 0/8 LR. MTAP deletion was associated with TP53 deletions in two HR MCL, that is supposed to confer resistance to PRMT5 targeted therapy (Sloan SL et al. Blood 2023). Deletion of the chromatin modifier MEF2B occurred in 3/8 HR MCL and 1/8 LR MCL. Two patients had deletion of SMARCA4 at diagnosis, that confers resistance to the BCL-2 inhibitor venetoclax (Agarwal et al. Nature Med 2018). Mutations in the NF-κB alternative pathway, responsible for resistance to ibrutinib, are found in both LR and HR patients. Conclusion In this small cohort of MCL patients included in a trial, complex structural alterations were identified by OGM at the time of diagnosis. OGM is a very promising technology that demonstrated its potential in the cytogenetic prognostic staging of MCL.

Material and Methods, Figure legends

Differentially expressed genes in murine B cell precursors

Efficacy of conventional chemotherapeutic agents alone or in combination with Trametinib in PDX B-ALL cells in vitro

List of fusion transcripts identified through RNA-sequencing

Diversity, equity, and inclusion (DEI) in research is important. This is the case not only because it is simply the right thing to do but also because DEI fosters collaboration, empathy, and psychological safety between scientists and clinicians as well as in our attitudes to and relations with patients. Inclusion of patient samples from diverse populations is critical to ensure that the full range of biological variabilities are represented in basic and clinical research. One important aspect is to ensure the possibilities of all researchers to use their talents to the fullest without structural limitations. Another is the broader societal benefit. Without policies that promote DEI values in access to academic positions, research funding, and mentorship regardless of, for example, ethnicity, religion, nationality, disabilities, sexuality, and gender, the complex challenges of today’s health care cannot be solved in a way that reflects the needs of the entire society in its complexity—minorities as well as majorities. There are no instant solutions, but all change starts with awareness. The European Hematology Association (EHA) has established a DEI task force with the goal to identify and address existing barriers to DEI in research within the hematology community such as those related to gender, ethnicity, and geographical disparities. Our motivation is based on the conviction that a broad representation of committed and talented people in our community will foster stronger research, more relevant educational activities, and better career tracks/opportunities in European hematology. However, developing better care for patients with hematological diseases is what EHA stands for and is at the heart of all EHA’s activities. We believe that a stronger focus on DEI values in all aspects of research will not only benefit scientists but also have a much wider positive impact on patient care. Recognizing the multiple ways that lack of DEI values in research can have direct and indirect impacts on patient care is a first critical step toward accelerating the implementation of DEI principles in our research communities. Fewer options to participate in research with inevitably greater difficulty in accessing novel therapies or diagnostic tests are clear examples of lack of inclusion from the patient perspective. Indirect impact on patient care also occurs, as the knowledge and experience gained through diverse, multicultural active clinical trial participation will not only benefit trial participants but also leave better opportunities for sharing and discussing difficult patient cases within expert networks. UNEQUAL ACCESS TO CLINICAL TRIALS Unequal access to clinical trials is a major obstacle to offering patients equal treatment opportunities. The median clinical development time for novel drugs is already close to 10 years.1 Not all novel therapies are successful, but some fundamentally change the survival outcomes for patients. For example, the use of BCL2 inhibitors in chronic lymphocytic leukemia2 and acute myeloid leukemia3 has led to tolerable, highly efficacious treatment regimens for patients with difficult-to-treat diseases. New classes of therapies, including chimeric antigen receptor T-cell therapy, have changed the treatment paradigm for many relapsed/refractory lymphomas completely. Patients without any previous good treatment options can now achieve long-term survival and possibly cure.4 The development of gene therapies for patients with inherited blood disorders such as sickle cell disease can dramatically improve quality of life for patients and their families.5,6 After pivotal studies and regulatory approval by the European Medicines Agency (EMA), health technology assessments and pricing negotiations further delay patient access to novel drugs. The median time from marketing authorization to inclusion in reimbursement lists in selected European countries is 227 days. Of note, this is for drugs that actually do get reimbursed; in reality far from all EMA approved, effective drugs eventually become available to patients in all countries.7 During the long development phase, subsequent regulatory reviews, and final reimbursement negotiations, potentially transformative therapies will only be available to patients that have access to clinical trials (with the exception of typically limited compassionate use programs). Therefore, we should strive for a situation where patients have more equal opportunities to be considered for enrollment in trials, possibly with trial adaptations to permit wider access. Unequal access to trial participation can be caused by several factors. The country of residence is a major determinant of trial availability. Patients with cancer from higher-income countries have more access to trials than patients from middle-income countries, with West European countries dominating the top 10 in access to clinical trials in 2015–2019.8 Access inequalities by national income are evident for industry sponsored trials, in which innovative drugs are typically tested for the first time.8 The number of trials registered in 2005-2019 was substantially higher, and distances to trial sites for citizens were lower in high-income countries. Although a recent cross-sectional study suggested that some lower and upper middle-income countries contribute substantially to the enrollment in global randomized clinical trials led by high-income countries, the subset of trials led by high-income countries that actively recruited in low-resource settings were more likely to be palliative intent compared with trials where enrollment was limited to high-income countries.9 Furthermore, only 8% of global trials in oncology were led from lower and upper middle-income countries and none of the middle-income and lower middle-income countries got market access drugs to the investigated drugs within 1 year after Food and Drug Administration (FDA) approval as compared to 13% of high-income countries.10 Thus, equity of access to novel drugs regardless of geography requires dedicated efforts by all stakeholders such as academic investigators, pharmaceutical companies, and regulatory authorities to ensure that less privileged countries are supported in development the necessary infrastructure to participate in clinical trials. As a first step, we, as academic investigators, can promote this by recommending inclusion of our experienced colleagues of less privileged countries, in and outside Europe, to pharmaceutical companies in the early stages of a clinical studies such as in steering committees and to recruitment of patients. ADVOCATING FOR FAIR TRAVEL BUDGETS FOR PATIENTS To prevent that long travel distances create inequity in access to novel therapies in trials, we, as investigators, need to be more aware of implementing trial support systems for patients with long travel distances, for example, when negotiation budgets and conditions in the start up phase. That is, to be more conscious of the fact that there are patients outside the immediate vicinity of the trial site for whom the trial could be relevant and will need coverage of trial expenses for patient and in some circumstances also for family members. This is particularly relevant for patients from rural areas with long travel distances to trial sites and for low-income families. For example, only 41% of patients from low-income families were willing to participate in cancer clinical trials that required more visits or travel compared to the site where regular care was provided (61% for higher-income families).11 WORKING TOWARD DECENTRALIZED TRIAL DESIGNS Decentralized clinical trial designs represent opportunities for getting trials to patients at home rather than requiring the patients to travel to the trial site. This can be facilitated by collaboration between researchers at a trial site and a local medical team, supported by digital technologies. Hematology trials frequently involve drugs with significant risk of serious adverse events. Thus, a decentralized trial design will require substantial training efforts of local staff and close oversight by the investigator, who retains final responsibility for noncompliance in relation to tasks delegated to third parties at a decentralized trial site.12 Results from recent pilot studies suggested that outpatient induction chemotherapy in acute myeloid leukemia (AML) and high-risk myelodysplastic syndrome (MDS) is feasible without compromising patient safety, provided that appropriate support systems are in place.13,14 Pragmatic solutions like this could also be applied in clinical trials to deliver as much experimental therapy as possible near to home. THOUGHTFUL DESIGN OF PATIENT INFORMATION AND ENCOURAGEMENT OF HEALTH LITERACY Even when trials are available at sites, not all patients are eligible for experimental therapies. A recent US study based on data obtained from 1200 institutions found a cancer treatment trial enrollment rate of 6.3%, higher than the historically estimated <5%, but too low for those whose only hope lies in access to new therapies.15 To our knowledge, no comparable European data are available, but there is no reasons to assume major differences. In a US study, lower-income patients had 32% lower odds of trial participation, a finding that was consistent across many patient subgroups, although proximity to trial site reduced the impact of income status.16 Poor health literacy could also lower likelihood of trial enrollment. Informed consent forms can easily cover more than 20 pages and, despite requirements for use of layman’s language, which may limit interest in trial participation for patients with low health literacy. Recommendations for simplifying informed consent documents have been provided, including substantial shortening of text parts, use of visual explanations, and removal of some legal aspects to appendices.17 In a survey conducted in eight European countries, at least 1 in 10 respondents had insufficient health literacy and close to 50% had limited health literacy, with social gradient toward higher numbers for financially deprived, low education level, and social status.18 Consistently, a recent systematic review found that patients’ understanding of fundamental informed consent components was low for important areas such as safety issues, risks, and side effects.19 If patients in clinical trials do not represent the whole community, there is the risk that differences in drug metabolism, side effect profiles, and outcomes will be missed. Ethnic subgroups are most often underrepresented in clinical trials. In a US study of 3103 patients enrolled in cancer trials, Black and Hispanic patients had lower phase 1 enrollment, with odds ratios of 0.46 and 0.25, whereas Asian patients had higher enrollment with an odds ratio of 1.38. These results withstood adjustments for important confounders such as age, sex, insurance status, marital status, income, cancer type, and travel distance.20 Informed consent forms are often only available in the dominant language of a country and ethnic minorities with limited language proficiency will not be able to participate in trials. A focus on patient friendly recruitment material for trials may facilitate enrollment of participants with broader ethnic, educational, and socioeconomic backgrounds. In addition to patient information in more languages, better interpretation support during trial participation is a key aspects for promoting equity and removing barriers related to ethnicity. ENCOURAGEMENT FOR FEWER EXCLUSION CRITERIA The application of numerous inclusion/exclusion criteria in clinical trials also leads to selection of a “healthier,” perhaps unrepresentative, group of patients. Fulfillment of organ function criteria, good performance status, and the absence of severe comorbidities are typical requirements, which exclude a significant proportion of cancer patients, many of whom are elderly, with comorbidities and have often undergone multiple prior therapies. In diffuse large B-cell lymphoma, patients ineligible for trial participation due to organ impairment constitute a subgroup with higher lymphoma-related mortality, suggesting that the patients left behind are in fact the ones with the highest unmet need.21 While inclusion/exclusion criteria are applied in part to safeguard against toxicity, each individual criterion should be considered in the context of the known characteristics of experimental therapy. This, rather than the default use of long standard check lists, will limit exclusion rates and ensure better generalizability of study results to the real-world patient population where the therapies will eventually be used with less restrictions. For example, patients with human immunodeficiency virus (HIV) are often excluded from lymphoma trials, although treatment and outcomes of HIV-associated lymphomas in the era of antiretroviral therapy typically parallel those of patients without HIV in the real-world setting.22 In a similar fashion, reduced kidney function is a reasonable exclusion criterion if renal excretion is the main route for elimination of a drug. However, when appropriate information on pharmacokinetics is available, the alternative for patients with poor organ function could be adjusted dosing, rather than patient exclusion. PROMOTING APPROPRIATE USE OF PATIENT AND PUBLIC ENGAGEMENT Patient engagement in the planning and execution is a key aspect of inclusiveness and oblige investigators to explain and justify the trial design and enrollment plans to patient representatives. The patient involvement roadmap provided by the European Patients’ Academy (EUPATI) defines how patients can be engaged at multiple time points during the drug development process, as trained experts or as advisors.23 Patient engagement should ideally also reflect the patient diversity—that is, patient advisory boards should have a reasonable balance in gender, educational background, socioeconomics, and ethnicity to be able to fully promote the interests of a diverse patient population. In conclusion, there are several barriers to diverse participation in clinical trials and equity in early access to novel therapies in clinical trials. Some barriers are at the country/site level, with the largest trial sites clustered in urban areas within major academic institutions and in countries with well-developed healthcare systems. Embracing opportunities for novel trial designs with decentralized components may remove geographical barriers to some extent. Also needed are better national support systems for patients (and their families) traveling either across borders or within countries to get optimal treatment. At the study level, critical assessment of inclusion/exclusion criteria when study proposals are reviewed by authorities could facilitate inclusion of patient groups that resemble real-world patients without significant compromise on safety. Appropriate development of robust real-world data exploitation, in the era of digital medicine, is a path to exploring the current access to trial participation in Europe and identify limiting factors. Real-world data can also contribute to understanding the uptake of novel therapies across treatment sites and assess how this correlate with trial activity. However, this will require optimal quality and recording of both clinical data in interoperable formats between European countries. The development of European Health Technology Assessment and the European Health Data Space will contribute to this. However, first and foremost, research that uncovers the full extent of European inequities in access to clinical trials as well as their multiple causes and how they are addressed—including and especially those tied to residence, socioeconomics, and minority status—is warranted to fully understand the status of DEI in European research and to pave the way for removal of the key limiting factors. ACKNOWLEDGMENT The authors would like to thank research coordinator Stine Kjær Morthorst for assistance with manuscript layout. AUTHOR CONTRIBUTIONS TCE-G and KG conceptualized and drafted the manuscript, and all authors participated in the editing of the content and approved of the final version. EHA Diversity, Equity, and Inclusion Taskforce: https://ehaweb.org/organization/be-part-of-eha/eha-taskforce-on-diversity-equity-and-inclusion/. DISCLOSURES TCE-G reports previous employment at Roche (ended within 24 months) and speakers fee from AbbVie (2021). MC reports research funding from Cyclacel and Incyte, is/has been an advisory board member for Astellas, Novartis, Incyte, Jazz Pharmaceuticals, Pfizer, and Servier; and has received honoraria from Astellas, Novartis, Incyte, Pfizer, and Jazz Pharmaceuticals. MD reports research support (institution) from AbbVie, Bayer, BMS/Celgene, Gilead/Kite, Janssen, Roche; speakers’ honoraria from Astra Zeneca, Beigene, Gilead/Kite, Janssen, Lilly, Novartis, Roche; is an Editor for HemaSphere; and Scientific Advisory Board: Astra Zeneca, Beigene, BMS/Celgene, Gilead/Kite, Janssen, Lilly/Loxo, Novartis and Roche. KD reports Consulting (C)/advisory role (A)/honoraria (H), Research (R) from: AbbVie (C, H, A), Celgene/BMS (A, H, R), Janssen (H, A), Novartis (C, A, H, R), CTI BioPharma Corp (C, A, H), Roche (A, H), GSK (A, H), Astellas (R), Agios (R), JAZZ (A, H), Daichi Sankyo (A, H). JG reports grant funding from AZ, Janssen and BMS; PI of clinical trials: Abbvie, Janssen, Morphosys, Genmab, Roche, Vertex, and Lilly; and Honoraria for Advisory Boards/speaking: Abbvie, Amgen, Janssen, Kite/Gilead, and Novartis. KG reports research grant from Janssen Pharma; advisory board member GSK and Nanexa; collaboration with Novo Nordisk. All the other authors have no conflicts of interest to disclose.