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Introduction Chronic myelomonocytic leukemia (CMML) is associated with a 15-30% risk for blast transformation (BT) over 3-5 years. Post-BT survival remains dismal with a median overall survival (mOS) of ~6 months (mo), even with intensive therapies. Although genetic drivers are identified in >40% of BT-CMML cases (Carr, 2021), mechanisms of BT remain to be elucidated. This multicenter study examines risk factors for BT in CMML and predictors of post-BT survival. Methods CMML patients at Mayo Clinic (n = 400, 47%) and MD Anderson Cancer Center (n = 449, 53%) were included with IRB approval. Analyses used clinical and molecular data at diagnosis or first referral in chronic phase (CP) and again at BT. Categorical variables were compared by Chi squared and continuous by Mann-Whitney U or Kruskal-Wallis tests. Multivariate analyses used Cox proportional hazards models with binarization via receiver operator curves. Kaplan-Meier analyses were censored at hematopoietic cell transplantation (HCT). P < 0.05 was considered significant. Calculations used BlueSky (v10.3.1) or Prism (v10.2.3). Results Of 849 CMML patients (median age 71 years, 32% female, 90% white) included in the study, 133 (16%) underwent BT. In comparison to CP-CMML without BT, those with BT were more likely (p < 0.05) to have had higher WBC counts (15.1 vs 11.4 x109/L), higher absolute monocyte counts (2.9 vs 2.2 x109/L), lower platelet counts (84 vs 102 x109/L), have circulating immature myeloid cells (52% vs 37%), and be classified as myeloproliferative (MP)-CMML (58% vs 44%) or CMML-2 (33% vs 17%) at diagnosis/first referral in CP. More mutations were detected in BT-CMML than in CP-CMML (mean 3.2 vs 2.8, p = 0.002). Mutations in RAS (NRAS, KRAS, BRAF, CBL, PTPN11; 51% vs 40%, p = 0.02) and signaling (CSF3R, FLT3, JAK2, SH2B3; 15% vs 7%, p = 0.004) pathway genes were more frequent in BT-CMML. Conversely, there were fewer BT-CMML patients with the favorable ASXL1WT/TET2MT genotype compared to CP-CMML (22% vs 33%, p = 0.004). Multivariate analysis identified MP-CMML (hazard ratio [HR] 1.5, p = 0.04), CMML-2 (HR 2.4, p < 0.001), and the presence of ≥4 somatic gene mutations (HR 1.8, p = 0.002) as risk factors for BT whereas the ASXL1WT/TET2MTgenotype was protective (HR 0.45, p = 0.002). The ASXL1WT/TET2MT genotype was also protective in the MP-CMML (HR 0.49, p = 0.04) and RAS-mutated (HR 0.35, p = 0.005) subgroups. Amongst BT-CMML cases, the median time to BT was 10 mo from diagnosis/referral. Compared to their CP assessment, patients in an overlapping Mayo Clinic BT-CMML cohort (n = 156, median age 69 years, 35% female) were more likely to have NPM1 (24% vs 3%, p < 0.001) and IDH2 (14% vs 1%, p = 0.01) mutations at BT. Amongst cases with paired molecular evaluations (n = 44), 7 (16%) acquired new mutations, including FLT3-ITD (n = 2) and NPM1 (n = 2). Conversely, 6 (14%) lost mutations, including TET2 (n = 3), SRSF2 (n = 2), CBL, NRAS, or PTPN11 (n = 1 each). There were no differences in variant allele fractions in driver genes present at CP and BT. Abnormal karyotypes were more prevalent at BT than in CP (60% vs 34%, p < 0.001), and 26 (25%) patients with a normal karyotype in CP acquired structural (65%) and/or numerical (69%) changes at BT, including 6 (23%) that acquired a complex karyotype. Acute myeloid leukemia defining translocations were seen in 4 (4%) cases: 2 with t(8;21) and 1 each with inv(3) and t(10;11)(KMT2A::TET1). After considering mutation and karyotype changes, only bone marrow blasts ≥30% (HR 1.7, p = 0.04) were independently prognostic for OS after BT (mOS 4 mo). Compared to supportive care (n = 50, mOS 1.3 mo), OS was improved by hypomethylating agents (HMA, n = 14, mOS 16 mo, HR 0.3, p < 0.001) or induction chemotherapy (n = 56, mOS 8 mo, HR 0.3, p < 0.001), but not by HMA + venetoclax (n = 11, mOS 6 mo, HR 0.7, p = 0.4). Allogeneic HCT (n = 28) improved mOS to 46 vs 3 mo (p < 0.001). Amongst 4 patients with paired whole genome sequencing before and after BT, 3 had increased copy number alterations (including 2 with loss of heterozygosity, 2 with gains, and 3 with deletions) while the 4th acquired novel likely pathogenic somatic mutations (MUC4, BAX, WNK2). Conclusions Survival in CMML after BT remains exceptionally poor. In this multicenter cohort, MP-CMML, CMML-2, and the presence of ≥4 somatic gene mutations were identified as risk factors for BT, with the ASXL1WT/TET2MT genotype being protective. Following BT, bone marrow blast burden ≥30% was an independent adverse predictor of survival.

Introduction: Outcomes from multidisciplinary lymphoma tumor boards in the molecular era are limited, and the effects of transitioning to virtual formats during the COVID-19 pandemic are not well-documented. This study evaluates how the transition of the Mayo Clinic Lymphoma Tumor Board to a virtual format has impacted its effectiveness and operations. The board, part of the International Mayo Clinic Care Network (MCCN), involves case presentations, subspecialist reviews, and collaborative recommendations. Methods: The Mayo Clinic Lymphoma Tumor Board, an integral part of the Mayo Clinic Care Network (MCCN), conducted a comprehensive review of lymphoma cases from 2014 to 2024. The board's review process involves a structured approach including the presentation of clinical case details, radiology and hematopathology findings, proposed treatment options, relevant literature review, and discussions. From 2014 to 2024, the Mayo Clinic Lymphoma Tumor Board reviewed a total of 722 patients. The review process involves a multidisciplinary team, including physicians, pharmacists, clinical research associates, and trainees. Recommendations and changes related to radiology interpretation, pathologic diagnosis, and treatment approaches were documented and tracked prospectively. In March 2020, the board transitioned to a virtual format due to the COVID-19 pandemic. This shift allowed for remote participation and continued collaborative review while maintaining the board's structured approach and documentation practices. Results: In a total of 722 patients, changes in care were identified in 423 patients, including 287 with newly diagnosed lymphoma and 136 with relapse or refractory disease. Among those who experienced changes, 94 had diffuse large B-cell lymphoma, 49 had follicular lymphoma, 39 had marginal zone lymphoma, 36 had classical Hodgkin lymphoma, and 29 had mantle cell lymphoma. Prior to the COVID-19 pandemic, 431 patients were analyzed, with 217 (50.3%) experiencing changes. A total of 268 changes were documented among these patients. Changes in radiologic interpretation occurred in 9 patients (2.1% of 431 total patients). Pathologic diagnosis changes were noted in 42 patients (9.7%). Additional testing was recommended for 73 patients (16.9%), and clinical management was altered for 144 patients (33.4%). After transitioning to a virtual format, 291 patients were reviewed post-COVID, with 206 (70.8%) having recommended changes. The total number of change recommendations was 322, reflecting increases across all components compared to previous data, with adjustments for varying numbers of patients reviewed. Specifically, radiologic interpretation changes occurred in 21 patients (7.2%), pathologic diagnosis changes in 57 patients (19.6%), additional testing recommendations for 85 patients (29.2%), and clinical management alterations in 159 patients (54.7%). Conclusion: Transitioning to a virtual format in the Mayo Clinic Lymphoma Tumor Board's continued to demonstrate the effectiveness, with increased changes in diagnostic interpretations and clinical management. These results illustrate the potential of virtual tumor boards to improve collaborative decision-making and adapt to evolving clinical needs.

Introduction: Considerable variation has been observed in the prevalence of monoclonal gammopathies across the globe. Although the prevalence of monoclonal gammopathy of undetermined significance (MGUS) has been evaluated in two hospital-based studies in India, no data exists on its prevalence in community-based settings amongst the rural Indian population. Objectives: To determine the prevalence of MGUS in a rural Indian population in a community-based setting. Methods: A cross-sectional study was conducted across 58 agrarian villages/hamlets of a tribal (aboriginals) district and 8 agrarian villages of a Non-Tribal district of Western India spreading over 2299 square miles (sq-mi), as part of SIMPLe (Screening Intervention for Myeloma and Prevention of Lifestyle diseases) study. For the complete study population, demographic details, medical history, and blood samples were collected after a thorough medical examination. Hemograms and serum protein electrophoresis (SPEP) were performed in all individuals. SPEP was performed using on-site capillary zone electrophoresis. Serum immunofixation electrophoresis (SIFE), and biochemistry (liver and renal function tests) were performed for those with abnormal SPEP graphs (those with M spike and those with abnormal bulges in beta-2 or gamma region suspicious of MGUS). Patients with monoclonal protein on SPEP or SIFE were further assessed for any smoldering/ multiple myeloma features. The data was analyzed using JMP ver. 17.2.0. Results: A total of 10,024 individuals were screened and data was analyzed for 9283 (8527 Tribal + 756 Non-tribal) individuals. The prevalence of MGUS in the study population was 62 (0.66%) and was 1.79% above the age of 55y (62 of 3447w). The median age of individuals with MGUS was 65y (IQR 59-72) with male preponderance. None of the patients satisfied the criteria for smoldering or multiple myeloma using IMWG criteria. The median Hb of the study population was 12g/dL (IQR 11.4-13). Among those with MGUS, the distribution of heavy and light chains was IgG - 83.33%, IgA - 16.67%, with none having IgM/ IgD paraprotein, Kappa - 50%, and Lambda - 50%. Two individuals only had light chain MGUS. There was no statistically significant difference between the tribal and non-tribal populations (aged >45y) in the incidence of MGUS (1.798% Vs. 1.745%, p=0.78), total protein levels (7.71 vs. 7.19 g/dL, p=0.87) and albumin-globulin ratio (1.54 vs 1.62, p=0.77) with numerically more patients having polyclonal gammaglobulinemia in the tribal population. The low Hb reflected the statistically lower Hb levels in the tribal population (9.1±4.2 Vs. 12.39±1.8g/dL, p-0.021) owing to concurrent hemoglobinopathies (sickle cell/ thalassemia traits). Conclusion: The prevalence of MGUS in the rural population of Western India is low at 0.66%, rising to 1.79% in individuals over 55 years, predominantly affecting older males, with IgG MGUS being the most common type. There are no significant differences in MGUS prevalence, total protein levels, or Albumin-globulin ratios between tribal and non-tribal populations over 45 years. Our study comprehensively describes the prevalence of MGUS in rural community settings in India. The background prevalence appears to be lower compared to the Western (both USA ~3% and European~5%) population.

Background: Hematopoietic stem cell transplant (HSCT) based gene therapies (GT) have successfully demonstrated significant reduction in vasocclusive crises (VOCs) associated with sickle cell disease (SCD). The efficacy and safety of these products is well established across multiple clinical trials (Kanter et al. NEJM 2022, Frangoul et al. NEJM 2024). This led to the Food and Drug Administration (FDA) approval of the lentiviral-based gene addition product (lovotibeglogene autotemcel) and CRISPR-Cas9 based gene editing product (exagamglogene autotemcel) for patients with SCD above 12 years of age. As these therapies have a different logistical process compared to a standard allogeneic HSCT, there is a need to develop a collaborative transition of care plan for these patients and families prior to and long after completion of transformative therapies. Methods: Upper Midwest Sickle Cell Curative Therapies Consortium is a collaborative model including multiple stakeholders between 7 centers across the upper Midwest United States, the regional community-based organization (CBO) and National Marrow Donors Program (NMDP). The structure and workflow for this model was presented previously (Blaylark et al. ASH 2023). With the advent of commercial GTs, we developed a multi-specialty care model in collaboration with community stakeholders to address diverse patient and logistical needs for smoother transition to and from these therapies. Discussion: The initial transition is a period of potential gaps in medical care and often high anxiety for patients and families. Thus, when patients and families are considering GT, our care model engages a multidisciplinary team. As part of the comprehensive evaluation prior to gene therapy, an initial shared collaborative checklist includes an extensive medical history, assessment of treatment plan, an individualized pain plan and adherence, transfusion planning (simple or exchange) with setting of target hemoglobin and hemoglobin S% targets, and coordination of multi-specialty consults including apheresis, fertility preservation, child life, and social work. Additionally, pain, psychology, and integrative medicine specialists address not only ongoing concerns, but also help develop a plan for future transition back to the primary site of SCD care (“re-transition”) after GT. Patients undergo neuropsychological evaluations to establish baseline functioning and the role of chronic pain and fatigue, as GT can significantly impact long term cognitive functioning, emotional coping with transitions, and overall daily functioning. When appropriate and available, warm handoffs are encouraged between centers within each of these specialties. Our team also reviews available resources for education and ongoing support through the process and after from national and regional CBOs. Similarly, the post-GT transition is also a period of potential medical care gaps and high anticipated anxiety and concern, as patients go through significant unfamiliar adverse effects followed by the potential for persistent freedom from VOCs. In the post-GT transition, ongoing psychology, integrative medicine, and pain team support; peer mentoring; and support groups are critical for a smooth re-transition to post-GT care and further successful re-transition back into the community. Using this interdisciplinary approach across GT clinical trials, we successfully weaned opioids in 83% of patients (5/6) by day 60 post-GT infusion and successful re-transition of these patients, further highlighting the role of interdisciplinary care. Our team's collaborative approach to SCD care with sickle cell specialists, transplant team and other care providers and CBO continues into the long term follow up period, including ongoing supportive services for both patients and their families. Conclusion: As newer therapies are developed and approved for transformative SCD care, development of a transitional model with early engagement of an interdisciplinary team is critical for empowering sickle cell warriors and for their successful transition back into the community.

Introduction: For cardiac transthyretin (ATTR) amyloidosis, bone scintigraphy has emerged as a noninvasive diagnostic tool. The use of different tracers, namely Pyrophosphate (PYP), 3,3-diphosphono-1,2-propanodicarboxylic acid (DPD), HydroxymethyleneDiphosphonate (HMDP), allow for the detection of amyloid deposits in the heart. The aim of this systematic review is to evaluate the diagnostic test accuracy of bone scintigraphy in ATTR and light chain (AL) amyloidosis. Methods: As part of the ASH AL Amyloidosis Diagnostic Guideline, we performed systematic reviews for 7 prioritized PICO questions related to the screening, diagnosis and organ involvement evaluation of AL amyloidosis. Electronic searches were conducted on PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024. Two reviewers independently and in duplicate performed title and abstract screening and full text article screening on LASER AI, with conflicts resolved by a third reviewer. Studies were eligible if they included patients that performed both a bone scintigraphy scan and an endomyocardial biopsy for suspicion of ATTR amyloidosis. Test positivity for the visual score was defined to be ≥2, for the heart over contralateral (H/CL) ratio it was > 1.5 at one hour and >1.3 at 3 hours. Diagnostic test accuracy measures of interest were sensitivity, specificity, positive and negative predictive value. Statistical analysis was performed on STATA 18.0. Grading of Recommendations Assessment, Development and Evaluation (GRADE) was used to assess the certainty of evidence. Results: After deduplication, we retrieved 29,237 studies from electronic databases. 12 studies with 1127 patients reported on visual score in patients suspected to have ATTR amyloidosis. The pooled sensitivity for visual score was 96% (95% CI 92.0-98.0) while specificity was 90% (95% CI 84.0-95.0) (Certainty of evidence (COE): Moderate ⨁⨁⨁◯). 3 studies reported on ATTR visual score in combination with evaluating for monoclonal gammopathy, the pooled sensitivity was decreased to 93% (95% CI 65-99) and while specificity increased to 99% (95% CI 80-100) (COE: Moderate ⨁⨁⨁◯). H/CL was evaluated in 5 studies with 189 patients; pooled sensitivity was 97% (95% CI 89.0-99.0) and specificity was 88% (95% CI 64-97) (COE: Low ⨁⨁◯◯). We also performed subgroup analyses for the diagnostic test accuracy of visual score for the different tracers (PYP, DPD, HMDP) in patients suspected to have ATTR amyloidosis. DPD was found to have the highest sensitivity which was found to be 97% (95% CI 91.0-99.0) and a specificity of 95 (95% CI 86.0-98.0) (4 studies, n = 297 COE: Moderate ⨁⨁⨁◯). The sensitivity and specificity for PYP was 95% (95% CI 87.0-98.0) and 90% (95% CI 79.0-96.0) (7 studies, n = 377 COE: Moderate ⨁⨁⨁◯). 1 study reported on HMDP with a sensitivity and specificity of 79% (95% CI 49.0-95.0) and 100% (95% CI 59.0-100.0) (COE: Low ⨁⨁◯◯). Conclusion: Bone scintigraphy has a high sensitivity and specificity for the diagnosis of ATTR amyloidosis, particularly in patients without a monoclonal gammopathy.

Introduction: Although endomyocardial biopsy is the gold standard, echocardiography, and Cardiac Magnetic Resonance (CMR) play a pivotal role in the diagnosis of cardiac amyloidosis. In this systematic review, we aim to estimate the diagnostic test accuracy (DTA) of CMR and echocardiography for cardiac amyloidosis. Methods: As part of the American Society of Hematology guidelines on the diagnosis of Amyloidosis, we searched PubMed, Embase, and the Cochrane Central Register of Controlled Trials from inception till January 2024 for relevant studies. Two reviewers independently performed title and abstract screening and full-text article screening on LASER Al and extracted relevant data using a piloted Excel sheet. We performed statistical pooling using Stata 18.0 software. We evaluated risk of bias using Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess the certainty of the evidence. We report diagnostic test accuracy as sensitivity (95% confidence interval) and specificity (95% confidence interval). Results: After screening 29,237, we included 9 studies assessing DTA of late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) using an endomyocardial biopsy (EMB) as a reference test in patients with amyloidosis (light chain and ATTR). The majority of studies didn't report on the type of amyloidosis where only 2 out of 9 were in patients with light chain amyloidosis. The pooled estimates for sensitivity and specificity of LGE are 0.95 (0.88. 0.98), and 0.81 (0.60, 0.92), respectively. We did a sensitivity analysis and included only LGE suggestive for amyloidosis which didn't change sensitivity but led to an increase in specificity for amyloidosis to 0.87 (0.76, 0.94), respectively. The pooled estimates were based on moderate certainty in the evidence. For 2-dimensional echocardiography, we addressed DTA for different echocardiographic findings and we did not limit the reference to EMB. A panel of experts judged whether the reference was acceptable or not. Acceptable reference was EMB alone or a combination of extracardiac biopsy plus cardiac imaging (CMR or echocardiography) with or without positive cardiac biomarkers (troponin or BNP or NT-proBNP). Six studies (n=2063) addressed interventricular septum thickness (IVS), sensitivity was 0.77 (0.69, 0.84) and specificity was 0.71 (0.60, 0.81). 4 out of 6 studies used 12 mm as a cutoff while the other 2 studies used 13 mm as a cutoff. Only 2 studies (n=1667) assessed the DTA of posterior wall thickness (PWT), with sensitivity ranging from 0.76 to 1.00, and specificity ranging from 0.84 to 0.89. Six studies (n=438) addressed diastolic dysfunction (grade 2,3), with a sensitivity of 0.71 (0.40, 0.90), and specificity of 0.75 (0.64, 0.84). 7 studies (n=472) reported DTA of only diastolic dysfunction grade 3. When compared to diastolic dysfunction (grade 2,3, sensitivity decreases to 0.42 (0 28. 0.58) and specificity increases to 0.89 (0.83. 0.94). For E/A ratio, only 2 studies (n=127) were included. Sensitivity ranged from 0.45 to 0.65, and specificity ranged from 0.85 to 0.98. Four studies (n=1596) yielded a sensitivity of 0.86 (0.65, 0.95) and specificity of 0.76 (0.55, 0.89) of left ventricular global longitudinal strain (GLS). All except one used -17% as a cutoff for GLS. For apical sparing on GLS, pooled estimates from 8 studies (n=2253) led to a sensitivity of 0.72 (0.64, 0.78) and specificity of 0.78 (0.64, 0.88). There was a variation of cutoff across studies. The certainty of evidence for echocardiographic findings was low to moderate. Conclusion: CMR is a more accurate test with better performance compared to echocardiography.

Introduction: There are discrepant definitions of both iron deficiency and anemia in pregnancy. It is recognized that iron requirements increase during pregnancy, particularly in the third trimester, and that deficiencies should be corrected to avoid adverse maternal-fetal outcomes. While low dose iron supplementation is recommended for all pregnant persons (ACOG Bulletin 233), dosing through prenatal vitamins varies widely. Additionally, despite the epidemic of iron deficiency in reproductive-age females globally and availability of high-value biomarkers (e.g., ferritin), current guidelines only recommend screening for iron deficiency during pregnancy in the presence of anemia. As anemia is the terminal manifestation of iron deficiency and reference ranges vary by organization, these guidelines and practices warrant further investigation and discussion. Methods: Retrospective review and analysis of the electronic health record at Mayo Clinic (Rochester, MN) was performed for obstetric deliveries between June 2022 and May 2023. Iron deficiency was defined as a ferritin <50 mcg/L and anemia was defined as a hemoglobin <11 g/dL. Results: A total of 2,141 unique deliveries were identified. The median age at delivery was 31 years old (range: 15 - 45) with 82% identifying as white. Anemia was documented in 42% (n=904) of pregnancies at least once throughout gestation, with an increasing frequency of 2% (n=43) in the first trimester, 11% (n=230) in the second trimester, 17% (n=361) in the third trimester, and 38% (n=803) from admission for delivery through the peri-partum period. There were five documented pRBC transfusions prior to admission for delivery; however, from admission for delivery through the peri-partum period, there were a total of 102 documented pRBC transfusions. In total, 15% (n=318) of pregnancies were screened for iron deficiency through ferritin testing. Ferritin levels were measured 415 times with 23% (n=96) occurring between the last menstrual period and 12 weeks gestational age (WGA), 24% (n=100) occurring between 13-27 WGA, 40% (n=164) occurring between 28-40 WGA, and 13% (n=55) occurring post-partum. Iron deficiency was found in 70% (n=67), 79% (n=79), 80% (n=164), and 78% (n=43) of measured ferritin levels, respectively. Despite the paucity of screening, prescriptions for oral iron increased throughout gestation with supplementation in pregnancy for 8% (n=170) prior to 12 WGA, 14% (n=290) for those 13-27 WGA, and 23% (n=489) for those 28-40 WGA. Similarly, intravenous iron infusions increased throughout gestation with supplementation in pregnancy for 0.3% (n=7) prior to 12 WGA, 0.7% (n=16) for those 13-27 WGA, and 4% (n=95) for those 28-40 WGA. Prenatal vitamins were documented in over 90% of pregnancies throughout gestation, although the majority were non-prescription and contained variable amounts of elemental iron. Conclusions: Iron deficiency in pregnancy is underrecognized and undertreated. It follows that the accuracy of current reference ranges for anemia in pregnancy are suspect without rigorous verification of replete iron stores in the reference population. Given potential implications for blood product utilization and prenatal care, additional studies are warranted to better characterize iron deficiency in pregnancy as well as clinical sequelae for both mothers and infants. Simultaneously, discussions are needed around current guidelines and recommendations for both screening and treating iron deficiency in pregnancy. Providers, institutions, and professional societies should pursue pragmatic quality improvement initiatives and equitable healthcare delivery efforts to optimize care for this vulnerable patient population at high risk of iron deficiency.

Oncoprotein-driven human cancers exhibit replication stress (RS), leading to an increase in DNA double-strand breaks (DSB). These DSBs are repaired by one of the three main pathways - homologous recombination repair (HR), non-homologous end-joining (NHEJ), and microhomology-mediated end joining (MMEJ). Cyclin D1 (CCND1) is one of the most overexpressed oncoproteins and is universally overexpressed in mantle cell lymphoma (MCL). While CCND1 overexpression drives cells into the S-phase, its specific effects on RS and DSB repair pathways are poorly understood. Here, we investigated the impact of CCND1 overexpression on RS and DSB repair mechanisms in MCL. First, the expression level of CCND1 positively correlated with heightened RS, as indicated by elevated p-RPA-S33 and p-RPA S8 levels, and increased DNA damage, assessed by g-H2AX, especially in the mitotic phase, across diverse cell models, including MCL. Since CCND1-overexpressed cells proliferate rapidly, we hypothesized that some DNA repair pathways might be upregulated to meet the demand for repairing the excess RS-driven DSBs. Reporter assays demonstrated that the MMEJ pathway was specifically upregulated upon CCND1 overexpression, whereas no significant changes were observed in the HR and NHEJ pathways. Furthermore, CRISPR interference (CRISPRi)-mediated knockdown of CCND1 in MCL cells led to a significant reduction in MMEJ activity. This finding suggests the specificity of CCND1 in mediating the upregulation of the MMEJ pathway. Consistent with this, increased MMEJ activity, assessed via foci formation and immunoblotting of DNA polymerase theta expression (POLQ, encoded by POLQ gene), the primary polymerase for the MMEJ pathway, correlated with CCND1 overexpression, suggesting the crucial role of MMEJ in DSB repair processes under CCND1-overexpressed conditions. Sincethe MMEJ pathwayplays a pivotal role in repairing DSB during mitosis, we assessed the dependency of MCL cells on MMEJ-mediated DSB repair for cell survival. As expected, genetic deletion or pharmacological inhibition (ART558 and novobiocin) of POLQ in MCL cells led to increased RS and increased unrepaired DNA damage during mitosis, ultimately leading to chromosomal instability, mitotic catastrophe, and apoptosis. Additionally, the deficiency of POLQ in MCL cells resulted in increased levels of single-strand DNA, another critical biomarker for RS. Second, we found that ATM deficiency, the second most common genetic alteration after CCND1 overexpression in MCL, further increased the cellular dependence on MMEJ. Interestingly, the accumulation of unrepaired DNA damage during mitosis was notably increased in ATM-deficient CCND1-overexpressed cells. When POLQ was inhibited, a significant antitumor effect was evident in MCL cells, including ibrutinib-resistant MCL, both in vitro and in vivo, and this effect was enhanced by ATM deficiency. Further, simultaneous inhibition of both ATM (AZD0156) and POLQ was synthetic lethal in MCL cell lines and primary tumor cells from patients with MCL. Mechanistically, we observed the direct binding of CCND1 to the POLQ promoter and a corresponding upregulation of POLQ mRNA in CCND1-overexpressing cells. Consistently, a significant overexpression of POLQ mRNA was observed in primary MCL cells, compared to other non-Hodgkin lymphoma cells without CCND1 overexpression. Moreover, the positive correlation between POLQ and CCND1 expression was further validated using syngeneic B-lymphoma cells with and without CCND1 overexpression. Importantly, CRISPRi-mediated CCND1 knockdown reduced POLQ mRNA expression and the dependency of MCL cells on the MMEJ pathway for survival. In addition, ATM deficiency showed a further increase of endogenous POLQ expression and foci formation in cells with CCND1 overexpression, suggesting ATM negatively regulates the MMEJ pathway, especially in the CCND1 overexpressed background. In summary, CCND1 overexpression leads to a substantial increase in RS, intensifying the reliance on MMEJ-mediated mitotic DSB repair. Within MCL, POLQ is crucial in mitigating the adversities of CCND1-driven RS. Our data suggest that targeting the MMEJ pathway via POLQ inhibition, particularly in the presence of CCND1 overexpression and ATM deficiency, emerges as a promising therapeutic approach in oncoprotein-driven hematologic malignancies such as MCL.

Background: Rituximab, gemcitabine, and oxaliplatin (R-GemOx) is a commonly utilized chemoimmunotherapy regimen for relapsed or refractory (R/R) diffuse large B-cell lymphoma (DLBCL), especially for patients ineligible for autologous stem cell transplant (ASCT) or chimeric antigen receptor T cell therapy (CAR T). R-GemOx is used as a comparator arm in several active phase III clinical trials for R/R DLBCL, including the POLARGO (polatuzumab vedotion and R-GemOx), STARGLO (glofitamab and GemOx), SUNMO (mosunetuzumab and polatuzumab vedotin), LOTIS-5 (loncastuximab tesirine and rituximab), and EPCORE DLBCL-1 (epcoritamab) studies. However, real-world data are limited to understand the patterns of use and outcomes of R-GemOx in the US. Methods: We developed a retrospective multicenter US cohort (known as LEO CReWE) of patients with R/R DLBCL and other aggressive B-cell lymphomas at the eight US academic centers participating in the LEO Cohort Study (NCT02736357). Patients first diagnosed with DLBCL (including transformed and high-grade B-cell lymphoma) from 2007 - 2022 who received second line (2L) or later therapy for R/R DLBCL with R-GemOx were included. Baseline characteristics, treatment, and follow-up data were abstracted by chart review. Index line of therapy was defined as the first receipt of R-GemOx therapy in the 2L or later setting. Intent for CAR T and/or ASCT was evaluated at each line of therapy based on medical records at the time of treatment initiation. Subgroup analyses were pre-planned in groups of special interest, including those treated with R-GemOx without intent for ASCT or CAR T, those treated as a bridge to CAR T, and those aged 70 and older. Results: 183 patients with R/R DLBCL treated with R-GemOx were included. At time of initiation of R-GemOx, median age was 68 years (range 21-88), with 71 patients (39%) aged 70+ and 18 (10%) aged 80+. Many patients had high risk features including 13% with high grade B-cell lymphoma and 56% with IPI 3 or greater. 21% had an ECOG performance status of 2 or greater. Patients received a median of 2 lines of therapy prior to the index line of R-GemOx (range 1-7). 52% of patients did not achieve a complete response (CR) to first-line therapy, and 20% relapsed <12 months from an initial CR. In all patients receiving R-GemOx, the overall response rate (ORR) was 45% (29% CR). At a median follow-up of 39 months, median EFS was 2.3 months (95% CI: 1.8-3.2), with 12-month EFS of 21% and a 24-month EFS of 15%. Median OS was 13.5 months (95% CI: 9.6-18.1), with a 12-month OS of 52% and a 24-month OS of 38%. In patients treated without intent for ASCT or CAR T, ORR was 33% (18% CR). Median EFS was 2.0 months (95% CI: 1.6-2.5) with 12- and 24-month EFS of 14% and 9%, respectively. Median OS was 9.5 months (95% CI: 6.6-16.1) with 12- and 24-month OS of 45% and 29%, respectively. In patients receiving R-GemOx as bridging to ASCT or CAR T, ORR was 57% (35% CR). 35% received CAR T and 14% received ASCT, while the remainder did not receive the intended therapy as part of this line. Median EFS was 3.6 months (95% CI: 1.8-5.2) with 12- and 24-month EFS of 28% and 25%, respectively. Median OS was 17.4 months (95% CI: 13.4-NR); 12- and 24-month OS were 61% and 50%, respectively. In patients aged 70+, ORR was 53% (33% CR). Median EFS was 2.3 months (95% CI: 1.6-5.2), with 12- and 24-month EFS of 20% and 18%, respectively. Median OS was 13.9 months (95% CI: 8.6-30.2); 12- and 24-month OS were 57% and 39%, respectively. Conclusion: This study represents the largest reported cohort of patients treated with R-GemOx in US academic centers to date. The ORR of 45% and CR rate of 29% CR, as well as median EFS and OS of 2.3 and 13.5 months, respectively, are consistent with findings from previous phase II studies; these results highlight that responses to R-GemOx are not durable and the vast majority of patients require additional therapy. This study demonstrates real-world evidence of the efficacy of R-GemOx in a large cohort of patients with R/R DLBCL from the US over a long period, including both transplant-eligible and -ineligible patients, and patients treated in the CAR T era. These data aid in providing a benchmark for active clinical trials in the rapidly evolving landscape of R/R DLBCL therapies and allow potential comparison to a real-world cohort of patients with a broad range of clinical characteristics.

Background: TP53-mutated (TP53mut) myeloid neoplasms (MN) have particularly poor survival. Discrepancies in defining TP53mut MN have impact on diagnostic work up, therapeutic decisions, and clinical trial enrolment. Methods: MN cases harboring TP53mut (variant allele frequency, VAF ≥2%) were classified based on bone marrow (BM) and peripheral blood (PB) blast % using the 4th revision of the WHO classification (WHO-4R). Biallelic loss was defined as (i) ≥2 mutations each with VAF ≥2%; (ii) single TP53mut VAF ≥2% plus 17p loss detected on karyotype, FISH, or SNP; or (iii) single TP53mut VAF ≥50%, whereas monoallelic loss was defined as single TP53mut VAF <50% without 17p loss. Primary endpoint was overall survival (OS) from diagnosis. Conditional Inference Trees (CIT) analysis was used to determine the true effect of a predictor. Results: We identified 580 cases including WHO-4R defined acute myeloid leukemia (AML, BM/PB blasts ≥20%, n=219, 37.8%), myelodysplastic syndrome (MDS) with excess blasts-2 (EB-2, BM 10-19% or PB 5%-19%, n=92, 15.9%), MDS with excess blasts-1 (EB-1, BM 5-9% or PB 2-4%, n=75, 12.9%), and the remaining were MDS with low blasts (-LB, BM <5% and PB ≤1%, n=194, 33.4%). Of the 578 cases evaluable for allelic status, 437 (75.6%) and 141 (24.4%) had biallelic and monoallelic TP53 loss, respectively. Higher frequency of biallelic loss was observed with increasing blasts. 63.2%, 73.3%, 78% and 86.3% of cases with MDS-LB, MDS-EB1, MDS-EB2, and AML had bi-allelic TP53 loss (P<0.0001). In a multivariable analysis, WHO-4R categories, VAF ≥10%, and biallelic loss were independent predictors of poor survival. CIT analysis further stratified the cohort into 4 groups with distinct survival: (1) MDS-LB (n=194, 33.4%); (2) MDS-EB1/EB2 and AML with VAF <10% (n=38, 6.6%); (3) MDS-EB1/EB2 with VAF ≥10% (n=149, 25.7%); and (4) AML with VAF ≥10% (n=199, 34.3%). MDS-LB cases could be further stratified based on allelic status and complex karyotype (CK): OS was poor for cases with biallelic TP53 loss and monoallelic TP53mut with CK compared to monoallelic TP53mut without CK, who had the most favorable survival (12.7 vs. 13 vs. 34.8 months, P<0.0001).MDS-EB1/EB2/AML with VAF<10% could also be stratified by CK: MDS-EB1/EB2/AML with VAF<10% cases without CK had the favorable survival compared to their counterparts with CK and MDS-EB1/EB2 with VAF ≥10% cases (26.2 vs. 5.6 vs. 6.3 months, P=0.003).MDS-EB1/EB2 with VAF ≥10% was a homogenous subgroup: Biological characteristics including the proportion of cases with biallelic TP53 loss, CK (P>0.9), monosomal karyotype (MK, P>0.9), del 5q (P=0.6), del 7q (P=0.4), and del 17p (P=0.2) were comparable between MDS-EB1 and -EB2 with VAF ≥10%. Importantly, median OS of MDS-EB1 and EB2 with VAF ≥10% was comparable (9.6 vs. 7.2 months, P=0.12). OS in this group was comparable regardless of the blast %, allelic status, or presence of CK.AML with VAF ≥10% had extremely poor survival: Median OS was 3.9 months. Survival of AML was equally poor irrespective of the mono- or biallelic (3.6 vs. 3.9, P=0.89) and non-CK vs. CK (1.8 vs. 3.9 months, P=0.09). Combined, our model would acknowledge poor survival of 514 (89.1%) cases. In contrast, retrospective application of the 5th edition of the WHO classification (WHO-5) and International Consensus Classification (ICC) would classify only 211 (36.4%) and 468 (80.7%) cases as biallelic/multi-hit TP53mut MN, respectively. Finally, the Harrell's c-index of the proposed model, WHO-5, and ICC was 0.66, 0.571, and 0.617, respectively. Conclusion: We provide evidence for subsequent refinements in classifying MN harboring TP53mut. Our salient findings include: (i) acknowledgement of CK as ‘biallelic equivalent’ in MDS-LB; as well as EB1/EB2/AML with VAF 2 to <10% cases; and (ii) demonstration of poor survival of MDS-EB1 and -EB2 with VAF ≥10% regardless of the allelic status. In conclusion, our proposed model acknowledged poor survival of a higher proportion of cases as TP53mut MN compared to the current models with a higher c- index.