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Abstract Introduction: BL and DLBCL are the two most common lymphomas associated with HIV infection. Notably, clinical trials often exclude HIV-positive patients and prior retrospective studies often lacked long-term follow-up on overall survival (OS). This has limited our knowledge about the influence of HIV status on survival in BL and DLBCL. Survival outcomes can also vary significantly across ethnic groups, influenced mostly by disparities in healthcare access and socioeconomic status. Additionally, survival rates differ among age groups, which may be attributed to tolerance to intensive chemotherapy and the presence of comorbid medical conditions. Our study primarily focused on comparing OS between HIV-positive and negative patients with DLBCL and BL in the real world. We also examined OS disparities among diverse ethnicities and age groups. Method: Patients diagnosed with DLBCL and BL were identified from the Cerner Health Facts database over five years from 2013 to 2018 using ICD-9 and ICD-10 codes. Within this cohort, individuals with a positive HIV status were identified through specific ICD-9 and ICD-10 codes. Demographic characteristics including age, gender, and ethnicity were collected for all patients, and they were stratified into distinct age groups: <20 years, 20-39 years, 40-59 years, 60-79 years, and 80+ years. OS was calculated for all patients from the time of diagnosis to time of death or hospice discharge. A multivariate cox regression model was employed to adjust for confounding variables. Results: The total number of patients diagnosed with DLBCL and BL was 10,534. Of these patients, 45.3% were female. The ethnic composition included 77% Caucasian, 10.3% African American and 12.7 % from other ethnicities. Among this population, 315 patients were HIV positive. In the cohort of DLBCL patients, 8,275 were HIV negative and 185 were HIV positive. In the cohort of BL patients, 1,944 were HIV negative and 130 were HIV positive. Among patients with DLBCL, HIV positive status had more than two-fold higher mortality rate compared to their HIV negative counterparts (HR=2.1, 95% CI 1.31 to 3.36, p=0.0018). Patients with BL who were HIV positive had no difference in OS in comparison to the HIV negative group (p=0.575). African American patients with DLBCL had almost 40% increased risk of mortality compared to Caucasian patients (HR=1.39, 95% CI 1.05-1.83, p=0.017). African American patients with BL had no difference in OS compared to Caucasian patients (p=0.3). Patients aged 60-79 years were found to have 44% higher risk of mortality compared to 40-59 age group (HR=1.44, 95% CI 1.13-1.83, p=0.0033) and patients aged 80 years or above were found to have more than two-fold higher risk of mortality in the DLBCL cohort (HR=2.16, 95% CI 1.63-2.87, p<0.0001). For patients with BL, those aged 20-39 had half the risk of mortality as compared to the 40-59 age group (HR= 0.50, 95% CI 0.28 - 0.87, p=0.014) whereas patients aged 80 or older had almost three times higher risk of mortality (HR = 2.87, 95% CI 1.81-4.57, p<0.0001). Conclusion: HIV status can significantly influence survival outcomes in patients diagnosed with DLBCL. Early identification of HIV infection, along with the initiation of prompt antiretroviral therapy and the administration of appropriate intensive chemotherapy regimens, is crucial for optimizing treatment outcomes in this patient population. Notably, our study indicates that African American patients exhibit a higher mortality rate compared to their Caucasian counterparts with DLBCL. This could be related to disparities in access to healthcare and treatment resources across different ethnicities. Moreover, it also indicates possible lymphoma biological heterogeneity in various ethnicities. Furthermore, elderly patients demonstrate increased mortality rates likely attributed to a greater prevalence of frailty, indicating the need for innovative less intense regimens for these patients with DLBCL and BL.

Abstract Introduction The LEO Comorbidity Index (LCI), comprising ten equally weighted comorbidity categories (respiratory, cardiovascular, digestive, hepatic, renal, autoimmune, diabetes, cancer history, HIV, and stroke), has demonstrated prognostic utility in patients with non-Hodgkin lymphomas. However, its predictive accuracy may vary with increasing age, due to age-related rises in comorbidity burden and physiological vulnerability. To investigate these dynamics, we evaluated the age-stratified predictive performance of LCI in patients with large B-cell lymphoma (LBCL), with a focused analysis on individuals aged 80+ years. We also examined which specific comorbidities most strongly influenced overall survival (OS) and developed a simplified, clinically applicable index tailored to this population. Methods We first included adults ≥40 years with newly diagnosed LBCL and recorded comorbidities from the LEO registry (USA, 2015–2020; n=1,652) to assess age-stratified predictive performance of LCI using the C-index. Next, we focused on patients 80+ years (n=263), pooled from the LEO cohort (n=147) and NiHiL registry (restricted to General Hospital, Prague, Czech Republic, 2010–2023; n=116). Comorbidities were collected from patient self-reports (LEO) and/or medical records (LEO/NiHiL). Univariate and multivariate Cox models were used. The primary endpoint was OS. Results Among the total LBCL population (n=1,652), LCI predictive performance improved by age category with C-index for patients <65 of 0.584, 65–79 years 0.579, and ≥80 years 0.647, indicating stronger discrimination in the 80+ group. Subsequent analysis focused on patients aged 80+ years (n=263; median age 83). Within this cohort, 34% had ECOG performance status (PS) 2–4, 66% stage III–IV disease, 59% elevated lactate dehydrogenase, 35% >1 extranodal site involved, and 58% International Prognostic Index (IPI) score of 3–5. A total of 377 comorbidities were reported, averaging 1.43 per patient (1.22 in LEO; 1.61 in NiHiL). LCI distribution was: 0 points in 24% (n=62), 1 point in 33% (n=88), and 2–5 points in 43% (n=113). Higher LCI scores had worse ECOG PS 2–4: 19% (LCI=0), 33% (LCI=1), and 43% (LCI ≥2; P=0.01), and inferior OS (median 6.9 years LCI=0, 3.0 years LCI=1, and 2.8 years LCI≥2, resp.; P=0.02). Presence of ≥1 comorbidity was associated with shorter OS compared to no comorbidities (HR=1.67, P=0.01). The LCI was an independent predictor of OS after adjusting for age (HR=1.18, P=0.01, C-index 0.623), IPI (HR=1.16, P=0.03, C-index 0.628) as well as for recently proposed SENIOR-IPI (HR=1.14, P=0.049, C-index 0.665). When evaluating individual comorbidities, heart disease (HR=1.54, P=0.01), stroke (HR=1.89, P=0.03), and recent malignancy (HR=1.99, P=0.02) were independent predictors of OS. Based on these findings, we developed a simplified LCI (sLCI) for use in 80+ patients incorporating only the three comorbidities (1 point each). Patients were categorized as sLCI: 0 (49%, n=129), 1 (44%, n=115), and 2–3 points (7%, n=19). sLCI scores 0, 1, 2–3 were associated with ECOG PS 2–4 27%, 37%, and 63%, respectively (P=0.01) and inferior OS: median 5.3 years (0), 2.5 years (1), and 1.4 years (2–3; P<0.01). sLCI remained an independent and strong predictor of OS after adjusting for age (HR=1.71, P<0.01, C-index 0.636), IPI (HR=1.66, P<0.01, C-index 0.635), and SENIOR-IPI (HR=1.60, P<0.04, C-index 0.659). The results were consistent in both NiHiL and LEO cohorts and remained significant among patients treated with anthracyclines (sLCI adjusted for age: HR=1.58, P<0.01, C-index 0.607; for IPI: HR=1.53, P=0.01, C-index 0.623; for SENIOR-IPI: HR=1.51, P=0.01, C-index 0.633). Conclusion Comorbidity burden becomes increasingly prognostic with higher age in LBCL patients. In the 80+ individuals, comorbidities – particularly heart disease, recent cancer, and stroke – have an independent impact on OS. While the original LCI captures the impact of broadly defined comorbidities, its prognostic utility attenuates in the 80+ patients, likely reflecting limited relevance of indolent chronic conditions in this population's constrained survival horizon. The sLCI, focused on the most prognostically relevant comorbidities, offers practical risk stratification. Incorporation of sLCI into clinical decision-making – alongside other prognostic indices – could better identify high-risk individuals and guide treatment strategies. Funding: NU21-03-00411, U01 CA195568.

Abstract Background The benefit of high-dose chemotherapy and autologous stem cell transplantation (ASCT) as a consolidation strategy after initial chemotherapy in peripheral T-cell lymphoma (PTCL) is currently unclear, and a randomized trial (EA4232/PTCL-STAT) to answer this question is currently underway. Angioimmunoblastic T-cell lymphoma (AITL) is a rare, aggressive subtype of nodal PTCL with poor prognosis and unique features. Here, we report a large-scale, real-world evidence on the role of ASCT in frontline AITL management. Methods We analyzed a national cohort of 5,827 patients diagnosed with AITL between 2004 and 2020 from the National Cancer Database (NCDB). Baseline demographic, clinical, and socioeconomic characteristics were assessed. Treatment modalities included chemotherapy alone, chemotherapy with ASCT, and no treatment. Overall survival (OS) was evaluated using Kaplan-Meier method and multivariable Cox proportional hazards regression. Propensity score matching (PSM) was performed to validate ASCT's treatment effect. Results Among patients with complete treatment information (n = 5,224), the median age at diagnosis was 68 years (range 20–90). Frontline treatments included chemotherapy alone (68.6%, n = 3,584), chemotherapy with ASCT (14.6%, n = 761), and no treatment (16.8%, n = 879). Compared with patients who did not receive ASCT, those who underwent ASCT were significantly younger (median 60.0 vs 68.0 years), more frequently treated at academic centers (81.5% vs 57.9%, p < 0.001), and more likely to reside in areas with higher educational attainment (p < 0.001). They exhibited lower Charlson-Deyo comorbidity scores (CDS), with a higher proportion having a score of 0 (82.8% vs 73.6%, p < 0.001), and were more likely to have advanced-stage disease (93.0% vs 86.9%, p < 0.001). Furthermore, a higher proportion of patients who received ASCT were diagnosed in more recent years (p < 0.001). Sex, race, and IPI score distribution showed no significant baseline differences. Median follow-up time was 81.1 months (95% CI: 77.4–84.9), and the median OS was 23.3 months (95% CI: 21.3–25.2) for the entire cohort. For patients receiving chemotherapy with ASCT, the median OS was 139.2 months (95% CI: 104.2–174.2). In comparison, chemotherapy alone yielded a median OS of 23.6 months (95% CI: 21.4–25.8), while patients who received no treatment had a median OS of 4.0 months (95% CI: 2.7–5.2); overall p < 0.001. Median OS also significantly improved with more recent diagnosis eras: 20.1 months for patients diagnosed in 2004–2009 (95% CI: 16.8–23.4), 23.9 months for those diagnosed in 2010–2015 (95% CI: 21.0–26.7), and 26.7 months for patients diagnosed in 2016–2020 (95% CI: 23.1–30.4) (p < 0.001). Analyses consistently demonstrated longer median OS in female patients (27.5 vs. 20.7 months in males, p <0.001), and in patients treated at academic centers (27.5 vs. 16.4 months at non-academic centers, p < 0.001). Median OS varied by race (White: 24.0 months vs. Black: 15.2 months vs. Others: 30.3 months; p = 0.017). Patients with higher household income and higher educational attainment experienced significantly improved survival (p = 0.005 and p = 0.017, respectively). Patients with early-stage disease, lower IPI scores, and lower CDS also showed significantly longer survival (p < 0.001 for all comparisons). Multivariate Cox regression showed that chemotherapy with ASCT significantly reduced mortality risk compared to chemotherapy alone (HR = 0.438, 95% CI: 0.364–0.527, p < 0.001). No treatment significantly increased mortality risk (HR = 1.941, 95% CI: 1.634–2.305, p < 0.001). PSM analysis further validated that chemotherapy with ASCT significantly lowered mortality risk compared to chemotherapy alone (HR = 0.608, 95% CI: 0.503–0.736, p < 0.001), after matching for age at diagnosis, sex, race, income, education level, academic center, stage, CDS, and diagnosis era. Conclusion This large-scale, real-world analysis suggests that chemotherapy followed by ASCT is associated with significantly improved overall survival in patients with AITL, supported by unadjusted Kaplan-Meier analysis, adjusted multivariate Cox regression, as well as PSM analysis. These data support ASCT as an important consolidation strategy for AITL in real-world practice.

Abstract Background Mosaic chromosomal alterations (mCAs) are large-scale somatic gains, losses, or copy-neutral loss of heterozygosity (CNLOH) detectable by genotyping of peripheral blood DNA. They represent a form of clonal hematopoiesis and are observed in 0.5-5% of cancer-free individuals. The presence of any autosomal mCA has been associated with >3-fold risk of hematological malignancies. In particular, mCAs occurring in regions related to lymphoid malignancies have an 11-fold increased risk of lymphoid malignancies and a 68.6-fold risk for chronic lymphocytic leukemia (CLL). Monoclonal B-cell lymphocytosis (MBL), the precursor state to CLL, is defined by <5×10⁹/L clonal B cells in otherwise healthy individuals and is classified as low-count (<0.5x109/L) or high-count (0.5-5x10⁹/L) based on clonal B-cell count. MBL is also associated with increased risk of lymphoid malignancy (beyond CLL), with 4.3-fold and 74-fold risk in individuals with low- and high-count MBL, respectively. We previously reported a significant enrichment of autosomal mCAs in MBL, demonstrating a 1.7-fold association in those with low-count MBL and a 50.5-fold association in those with high-count MBL. Whether mCAs independently predict lymphoid malignancy risk after accounting for MBL status is unknown. Here, we evaluated the impact of mCAs on risk of incident lymphoid malignancies in individuals with MBL and in individuals screened negative for MBL. Methods CLL-type MBL (CD5 positive) was identified using flow cytometry assay on peripheral blood. Participants were age ≥40, had no prior hematologic malignancy, and were enrolled through the Mayo Clinic Biobank or the Division of Hematology at Mayo Clinic, Rochester. Participants were followed for incident lymphoid malignancy, including CLL, with diagnoses confirmed by medical record review. mCAs with cell fraction >1% were detected from array-based genotyping of whole blood DNA. Cox proportional hazards models, adjusted for age and sex, estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for risk of developing an incident lymphoid malignancy in individuals with autosomal mCA versus those without an autosomal mCA. Results In 4,331 participants with available MBL and mCA status, the median age was 67 years, and 45% were male. Flow cytometry identified 3,231 individuals who screened negative for MBL, 754 individuals with low-count MBL, and 346 individuals with high-count MBL. Autosomal mCAs were present in 6.5% of individuals without MBL, 7.6% with low-count MBL, and 71.1% with high-count MBL. Over a median follow-up of 6.9 years, 237 individuals developed an incident lymphoid malignancy. The most common types were CLL, multiple myeloma, and diffuse large B-cell lymphoma. Ignoring MBL status, the presence of an autosomal mCA was associated with increased risk of lymphoid malignancy (HR = 2.65; 95% CI: 1.45–4.86; P = 0.002), replicating previous results. However, after excluding individuals with MBL, this association attenuated; those with mCA alone did not have a significantly elevated risk (HR = 1.60; 95% CI: 0.57-4.52; P = 0.38) compared to individuals without MBL or mCA. We next examined the effect of mCAs among individuals with MBL. In those with low-count MBL, the most frequent mCA events were 13q loss (2.1%), 12 gain (1.9%), and 4q CNLOH (1.2%), and individuals with an mCA had a borderline significant risk of developing a lymphoid malignancy (HR = 2.78; 95% CI: 1.01–7.67; P = 0.049) compared to those without an mCA. Similarly, in those with high-count MBL, the most frequent mCA events were 13q loss/CNLOH (31.2%), 12 gain (13.0%), and 11q loss (4.9%), and the presence of an mCA conferred an increased risk compared to those without mCA (HR = 1.51; 95% CI: 1.09-2.08; P = 0.012). Conclusions Autosomal mCAs were more frequent in individuals with high-count MBL compared to those with low-count or no MBL. mCAs showed limited predictive value for lymphoid malignancy among individuals without MBL. In contrast, in individuals with low-count MBL, autosomal mCAs emerged as a potential biomarker for identifying those at risk of developing a lymphoid malignancy. In high-count MBL, mCAs were also a biomarker, but were driven by known chromosomal abnormalities identified through clinical testing. These findings suggest that the utility of mCAs as a predictive marker for lymphoid malignancy is contingent on the presence of MBL and may inform risk stratification and surveillance strategies in this population.

Abstract Introduction: Monoclonal gammopathy of undetermined significance (MGUS) affects over 2 million individuals aged ≥70 in the US. Earlier detection of smoldering multiple myeloma (SMM) and multiple myeloma (MM) in individuals with suspected MGUS via bone marrow biopsy allows for earlier active monitoring and potential intervention, including with daratumumab for high-risk SMM. Risk prediction for the presence of SMM or MM with the iStopMM and Mayo Clinic models leads to decreased individual-patient and population-level resource utilization burden of bone marrow testing with the tradeoff of some missed non-MGUS diagnoses. We sought to quantify the value of earlier diagnosis, while additionally accounting for the recent results of the AQUILA trial, by assessing the lifetime cost-effectiveness of bone marrow testing strategies for patients with suspected MGUS. Methods: In this independent analysis free of industry influence, we used a decision tree with nested Markov cohort models to evaluate diagnosis and disease progression from MGUS and SMM to MM across 3 diagnostic strategies employing: (1) iStopMM risk prediction model versus (2) Mayo Clinic risk stratification and prediction model versus (3) a test-all strategy. Both risk prediction model performance characteristics were derived from the largest population-level prospective cohort study. Individuals in the MGUS state were monitored annually for disease progression with blood tests. The SMM state included two groups: those correctly diagnosed through biopsy and those misclassified as MGUS due to not undergoing biopsy under the prediction model triage rules (missed SMM diagnosis). As recommended by guidelines, diagnosed patients with non–low-risk SMM were monitored with blood tests every three months; those with low-risk SMM were tested every six months. All diagnosed SMM patients underwent imaging for bone lesions at diagnosis and annually for up to five years. Missed SMM patients were monitored at the same frequency as those with MGUS until disease progression. Early versus delayed myeloma diagnosis complications were informed by real-world multi-institutional quasi-experimental data of consecutively diagnosed patients with MM. MM treatment and outcomes across up to four lines of therapy were modeled exactly as previously published in a validated model. In additional scenario analyses, we assessed the impact of daratumumab monotherapy in the care of people with high-risk SMM across all 3 testing strategies by incorporating the progression free survival and overall survival benefit as reported in the phase 3 AQUILA study. The primary outcome was the incremental net monetary benefit (iNMB), reported across all accepted US willingness-to-pay (WTP) thresholds from a US health system perspective. We concluded with extensive deterministic sensitivity analyses and additionally quantified uncertainty across all model parameters simultaneously with 10,000 Monte Carlo simulations. Results: The iStopMM model was the cost-effective strategy yielding the highest NMB of all strategies at every WTP threshold, with per-patient cost and effectiveness of $188,300 and 10.21 QALYs, respectively. This strategy was dominant—costing less and producing more QALYs—than both the Mayo Clinic and test-all strategies. At the population level, use of the iStopMM model over the Mayo Clinic model and the test-all strategy yields iNMBs of $0.67 [95% CI: 0.2 – 1.14] billion and $3.13 [95%CI: 2.80-3.47] billion, respectively, in favor of the iStopMM strategy. The iStopMM strategy was the cost-effective strategy in 100% of 10,000 second order Monte Carlo iterations. In deterministic sensitivity analyses, the top three parameters the iNMB was most sensitive to were prediction model test characteristics (i.e., sensitivity and specificity) as well as the baseline prevalence of SMM. However, no parameter variation could change the conclusion that iStopMM is the cost-effective strategy. In scenario analyses incorporating benefit of daratumumab monotherapy in the care of individuals with high-risk SMM, the iStopMM model remained the cost-effective strategy. Conclusion: Using the iStopMM risk prediction model for marrow sampling in patients with suspected MGUS leads to cost savings per patient evaluated, both with and without incorporating daratumumab benefit in the care of individuals with high-risk SMM, as compared to both the Mayo Clinic model and testing all with bone marrow biopsy.

Abstract Introduction: TERT promoter (pTERT) variants are among the most frequent genetic alterations in human cancers, where they drive oncogenesis through telomerase reactivation. However, somatic, pathogenic pTERT variants have also been seen in non-cancerous conditions such as telomere biology disorders (TBD), where they attempt to rescue the bone marrow failure phenotype (adaptive compensation). We conducted this study to assess the phenotype and outcomes of pTERT mutations in TBD patients. Methods: After IRB approval, the Mayo Clinic institutional TBD database was queried to identify all patients with somatic pTERT mutations. We have designed a customized error corrected sequencing panel that covers somatic mutations (52 genes) associated with adaptive and maladaptive outcomes in TBD patients. This covers the promoter region for TERT and can detect variants down to 0.5% variant allele fraction (VAF) with 10,000 X sequencing depth. Clinical data was retrospectively abstracted. Results: We identified 7 pTERT variants (3 hotspots) in 6 (two females (33%), mean age 61 years, 4 alive). The three hotspots were: (1) c.-57A>C (2 individuals, mean VAF 17.1%; range 11.6%-22.6%), (2) c.-124C>T (4 individuals, mean VAF 12.9%; range 1.9%-41.3%), and (3) c.-146C>T (1 individual, VAF 1.2%). One individual had both the c.-124C>T (VAF 41.3%) and the c.-146C>T somatic pTERT variants, occurring in the context of a germline TERT variant. The median VAF for all 7 pTERT variants was 6.1% (range 1.2%-41.3%). The hotspot, c.-57A>C, occurred in the context of pathogenic germline TERT (VAF 49.9%) variants with pathogenic somatic co-variants in PPM1D (avg. VAF 1.5%). The second hotspot, c.-124C>T, occurred in the context of germline TERT (avg. VAF 49.6%) and RTEL1 (VAF 47.3%) variants with pathogenic somatic co-variants including ASXL1 (VAF 1%), DNMT3A (VAF 8%), and PPM1D (VAF 4%). Five of six assessable patients with pTERT variants had shortened telomere lengths (TL), with results pending for one individual. Among those with the c.-57A>C variant, granulocyte TLs were at or below the 10th percentile, while lymphocyte TLs were below the 10th percentile in one patient and below the 1st percentile in another. For those with the c.-124C>T variant, all granulocyte TLs were below the 1st percentile. Lymphocyte TLs in this group included one at the 10th percentile and two at or below the 1st percentile. The median follow up for all patients was 2 years. Hotspot 1 (c.-57A>C) variants were associated with normocellular bone marrow biopsies with one patient having normal blood counts and the other having chronic macrocytic anemia (grade 2) and thrombocytopenia (< grade 1). In patients with hotspot 2 and 3 somatic variants, bone marrow cellularity ranged from 15–50% (1 patient had grade 2-3 hypocellularity), with normal bone marrow morphology, except for polytypic plasma cells (10–15%) identified in a patient with IgG kappa multiple myeloma (currently MRD negative on maintenance therapy). This patient also had a history of head and neck cancer and follicular lymphoma. Of these four patients, only one had normal blood counts (co-occurring c.-146C>T variant); the rest had cytopenias (n=3, the worst being grade 2 thrombocytopenia), progressive macrocytosis (n=3), or eosinophilia (n=1). Comorbidities encountered in these patients included myasthenia gravis (1), hypogonadism (1), and sarcoidosis (1). Moreover, four patients (2 each for hotspots 1 and 2) presented with idiopathic pulmonary fibrosis, while liver fibrosis was seen in 4 patients (also 2 each for hotspots 1 and 2). At last follow up, none of these patients had documented progression to myelodysplastic syndrome or acute myeloid leukemia. Conclusions: We describe the spectrum and clinical features of somatic pTERT mutations in TBD patients. pTERT mutations involved the following hotspot regions, c.-124C>T, c.-146C>T, and c.-57A>C, and co-occurred with other somatic variants (i.e., PPM1D and DNMT3A). None of the 6 patients with pTERT mutations had a severe bone marrow failure phenotype or developed myeloid neoplasms at last follow up, exemplifying a unique mechanism of adaptive somatic rescue.

Abstract Mutations in non-coding regulatory elements are increasingly recognized as critical drivers of cancer development and progression. Among these, structural alterations such as duplications of super-enhancers (SEs), large clusters of enhancers that regulate key oncogenes, have emerged as significant contributors to oncogenesis. In T-cell acute lymphoblastic leukemia (T-ALL), a particularly aggressive hematologic malignancy, SE duplications have been identified in approximately 5% of human cases. These duplications frequently involve a non-coding region located approximately 1.3 megabases downstream of the Myc oncogene, a region known as N-Me. Despite the growing recognition of the role of SE duplications in T-ALL, functional studies to determine their molecular origins and contributions to leukemogenesis have been limited, largely due to the absence of suitable and genetically tractable preclinical models. This gap in knowledge hinders both our understanding of disease pathogenesis and our ability to design targeted therapeutic interventions. Here, we report the generation and characterization of a novel genetically engineered mouse model of T-ALL that spontaneously develops oncogenic SE duplications at the Myc locus. This model offers the first spontaneous in vivo system to investigate the origin, regulation, and oncogenic function of SE duplications. This model was created by conditionally stabilizing β-catenin in CD4⁺CD8⁺ double-positive (DP) thymocytes in combination with targeted deletion of the transcription factor HEB. This combination is sufficient to drive the development of aggressive T-cell leukemias that consistently harbor duplications of the N-Me super-enhancer. This finding recapitulates the genomic alteration observed in a subset of human T-ALL and provides a unique platform for mechanistic studies. We further demonstrate that the molecular events leading to SE duplication and oncogenic Myc activation unfold in a stepwise manner. At the preleukemic stage, stabilization of β-catenin alone is sufficient to enhance recruitment of HEB to the N-Me region. The simultaneous loss of HEB greatly increased chromatin accessibility at the N-Me enhancer. This altered chromatin landscape permits aberrant binding of transcription factors including TCF-1, which plays a critical role in T-cell development and leads to N-Me SE activation associated with significant three-dimensional chromatin reorganization. Chromosome conformation analyses in the leukemic cells reveal the formation of a novel chromatin loop that brings the activated N-Me SE into close spatial proximity with the Myc promoter, enabling oncogenic Myc transcription. These findings uncover a novel mechanistic pathway by which β-catenin and HEB interact to reshape the enhancer landscape and three-dimensional chromatin architecture, ultimately promoting SE duplication and aberrant Myc expression in T-ALL. β-catenin appears to play a dual role, first facilitating HEB recruitment under physiological conditions and then, upon HEB loss, permitting the reprogramming of enhancer activity through chromatin opening and ectopic transcription factor binding. Our data suggest that the cooperative interplay between signaling pathways and transcriptional regulators at enhancer elements can initiate structural genomic changes that drive malignancy. This work provides a long-sought preclinical model that faithfully mirrors key features of human T-ALL. Our findings open new avenues for understanding how non-coding regulatory mutations arise and exert oncogenic effects and have the potential to provide insights that may extend beyond T-ALL to other cancers driven by enhancer dysregulation. Moreover, by revealing molecular intermediates such as β-catenin, HEB, and TCF-1 in the regulation of enhancer activity, our findings identify potential therapeutic targets to disrupt the oncogenic enhancer-promoter interactions that underlie Myc-driven leukemogenesis.

Abstract Background: Intravenous (IV) isatuximab plus pomalidomide and dexamethasone (Isa-Pd) is approved for treatment in patients with relapsed/refractory multiple myeloma (RRMM) based on the ICARIA-MM study. Subcutaneous (SC) administration of Isa offers potential advantages such as shorter administration duration and greater patient comfort compared with IV routes. Isa SC via an on-body injector (OBI), an investigational wearable bolus injector, demonstrated safety and efficacy in a Phase 1b study in patients with RRMM. The IRAKLIA trial (NCT05405166) was the first Phase 3 trial evaluating the non-inferiority of Isa-Pd SC via an OBI vs Isa-Pd IV in patients with RRMM. Here, we report the findings of the IRAKLIA trial in the East Asian subgroup with RRMM. Methods: This global, multicenter, open-label study enrolledpatients aged ≥18 years with RRMM who had received ≥1 prior line of therapy (LOT) including lenalidomide and a proteasome inhibitor (PI). Patients were randomized 1:1 to Isa SC (1400 mg) or Isa IV (10 mg/kg) weekly in Cycle (C)1, then every 2 weeks in addition to P (4 mg orally daily, Day [D]1-21) and d (40 mg orally [20 mg if age ≥75 years] weekly). Treatment was administered in 4-week cycles and continued until disease progression, unacceptable toxicity, or patient withdrawal. Co-primary endpoints included overall response rate (ORR) and observed Isa concentration before dosing (Ctrough) at steady state (predose at C6D1). Key secondary endpoints included rate of very good partial response or better (≥VGPR), Ctroughlevel Cycle 2 Day 1 (C2D1), infusion reaction incidence, and patient satisfaction rate based on the patient experience and satisfaction questionnaire (PESQ) at C5D15. Results: The East Asian subgroup consisted of 105 patients from China (Mainland, n=82 and Taiwan, n=1) and Japan(n=22) (SC, n=50; IV, n=55). Baseline characteristics of the East Asian subgroup were generally balanced between the two arms and generally comparable to the overall global population (median age 62 years; median 2 prior LOT; 29.5% high-risk cytogenetics; 82.9% refractory to lenalidomide; 7.6% prior exposure to daratumumab). After a median of 13.0 months follow-up, ORR in the SC and IV arm was 74.0% and 70.9%, respectively (relative risk [95% CI] = 1.044 [0.815 – 1.335]). The mean (SD) of Ctroughat C6D1 was 502 (232) µg/mL for SC arm and 282 (123) µg/mL for IV arm. The geometric mean ratio (90% CI) comparing SC to IV for Ctrough at steady state was 1.756 (1.346 – 2.290). The ≥VGPR rates were 58.0% for SC and 50.9% for IV (relative risk [95% CI] = 1.139 [0.798 – 1.631]). The mean(SD) of C2D1 Ctroughlevel was 420 (161) µg/mL for the SC arm and 262 (111) µg/mL for IV arm. The geometric mean ratio (90% CI) comparing SC to IV for Ctrough at C2D1 was 1.673 (1.321 to 2.120). The infusion reaction incidence was 0% and 21.8% for SC and IV, respectively. Grade ≥3treatment-emergent adverse events were observed in 82.0% and 87.3% of patients in the SC and IV arms, respectively. Treatment discontinuation rates were 6% for the SC arm and 12.7% for the IV arm. Injection site reactions (ISRs) occurred in 4% (2/50) of patients in the SC arm and in 0.21% (2/964) of SC injections (all Grade 1), with 99.3% of SC injections completed successfully. Isa SC patients expressed higher satisfaction with their injection method, with 64.0% of patients reporting “satisfied” or “very satisfied” vs 52.7% of Isa IV patients (odds ratio [95% CI] = 1.594 [0.728 – 3.489]). Conclusions: The efficacy, safety and pharmacokinetic results between Isa SC vs IV + Pd in the East Asian population from the IRAKLIA study were consistent with the results of the overall global population, in which non-inferiority of ORR, Ctrough at C6D1, ≥VGPR and Ctrough at C2D1 was demonstrated and statistically significantly fewer infusion reactions and higher patient satisfaction were also noted for SC vs IV. These results support the potential use of Isa SC delivered via OBI in East Asian patients and demonstrate the potential of this delivery method to improve patient experience and practice efficiency.

Abstract Introduction: The CAR-T therapies ide-cel and cilta-cel are approved for patients (pts) with relapsed/refractory multiple myeloma (RRMM). The aim of this study was to determine the incidence, subtypes, and associated risk factors for subsequent primary malignancies (SPMs) in MM pts treated with CAR-T therapy in the real-world setting. Methods: A retrospective, multicenter observational cohort study was conducted of pts who received CAR-T therapy between May 2021 and Dec 2024 at 15 centers within the US Multiple Myeloma Immunotherapy Consortium. Logistic models were used for univariable analyses of invasive SPMs (excluding non-melanoma skin cancers). Variables significant at p < 0.10 were included as candidate variables in the multivariable analysis. Time to event endpoints were analyzed using Kaplan-Meier curves. Results: Of n=1460 CAR-T recipients, median follow-up from the time of CAR-T infusion for the entire cohort, ide-cel, and cilta-cel pts was 13.1, 16.9, and 10 months, respectively. A total of 55 invasive SPMs were noted in 53 pts (SPM incidence 3.6%). The incidence rate of SPMs was 4.55 per 1,000 person-years, based on 53 SPMs occurring over 11,646.14 person-years (calculated from CAR-T to the SPM diagnosis, death, or last follow-up). Baseline characteristics were similar for pts with no SPM versus SPM including: age at CAR-T (median 67 vs 65), female (36% vs 43%), Black (13% vs 16%), prior autologous transplant (87% vs 80%), lenalidomide for ≥2 years (31% vs 27%), high risk cytogenetics (23% vs 29%), and known clonal hematopoiesis (7.5% vs 9.9%). Differences were observed in baseline characteristics among pts with SPM versus no SPM for ≥2 prior alkylator lines of therapy (LOT) (82% vs 60%, p=0.002) and median prior LOT (6 vs 5, p=0.008). There was a trend for more patients with SPMs being age ≥70 (35% vs 37%, p=0.074). Of the 53 SPMs, 26 (49%) were myeloid (MDS or AML), 19 (35.8%) were solid, 7 (13.2%) were of T-cell origin, and 1 was a B-cell lymphoma. Of the T-cell SPMs, three were of T-LGL, though one of the T-LGL pts later developed an invasive CNS T-cell lymphoma (CAR-negative). There were four cases of confirmed CAR-positive T-cell SPMs (all pts treated with cilta-cel), of which two were indolent T-cell lymphoma of the GI tract and two were cutaneous PTCL. There was no difference in total incidence of SPMs among pts who received ide-cel (total=4.4%; myeloid=2.2%, T-cell=0.04%) versus cilta-cel (total=3%; myeloid=1.4%; T-cell=0.5%) (p=0.21). Median OS from the time of CAR-T therapy was 40.8 months for pts without SPM compared to 27.6 months for pts with SPM (p=0.4). Median OS did not differ by myeloid, solid, and T-cell subgroup: 26.4, 37.2, and 24 months, respectively (p=0.21). Median time from CAR-T cell to SPM was 12 months overall, and by subtypes of myeloid, solid, and T-cell was 13.2, 9.6, and 9.6 months, respectively (p=0.74). There was no difference in time to any SPM among pts receiving ide-cel versus cilta-cel (p=0.61). An earlier time to diagnosis of myeloid SPM was observed for cilta-cel versus ide-cel (4.8 vs 20.4 months; p=0.003). Median OS from the time of diagnosis of any SPM, myeloid, solid, or T-cell SPM was 9.6, 7.2, 15.6, and not reached in months, respectively (p=0.006), demonstrating that pts diagnosed with myeloid subtype SPM had inferior OS from the time of their SPM diagnosis compared to other subtypes. The cause of death of 4/11 myeloid SPM pts was the myeloid SPM itself. In univariable analysis for the entire cohort, age ≥70 (p=0.079), ≥5 prior LOT (p=0.012), and ≥2 prior alkylator LOT (p<0.001) were associated with higher risk for SPM. In multivariable analysis, ≥2 LOT containing alkylators was associated with higher risk of SPM (p=0.005). For the univariable analysis of the myeloid subgroup, ≥2 prior alkylator LOT (p=0.016) and ≥2 years of lenalidomide maintenance (p=0.063) were associated with higher risk of SPM. In multivariable analysis, ≥2 years of lenalidomide (p=0.065) was associated with a trend toward increased risk of myeloid SPM. Conclusions: With a median follow up of 13.1 months, the incidence of developing a SPM following CAR-T in pts with RRMM was 3.6%, of which approximately half were myeloid malignancies. There was no difference in SPM incidence when comparing the two CAR-T products. Pts treated with ≥2 alkylator LOT had a higher risk of SPM in multivariable analysis and may warrant additional monitoring for SPM development.

Abstract Background In patients with myelofibrosis (MF) undergoing allogeneic hematopoietic cell transplantation (allo-HCT), graft-versus-host disease (GVHD) prophylaxis has traditionally included a calcineurin inhibitor (CNI) plus methotrexate (MTX). We conducted a retrospective study comparing the safety and efficacy of post-transplant cyclophosphamide (PTCy)-based GVHD prophylaxis to CNI-based regimens. Methods This study was approved by the Mayo Clinic IRB. Patients with myelofibrosis who underwent allo-HCT after 2016 at Mayo Clinic in Arizona and Florida were included. Categorical variables were compared using Chi-square or Fisher's exact tests. Overall survival (OS) was defined from transplant to death, and progression-free survival (PFS) from transplant to relapse or death. OS and PFS were estimated using Kaplan-Meier methods; univariate differences were assessed with log-rank tests. The cumulative incidence of acute and chronic GVHD and time to neutrophil and platelet engraftment were analyzed using competing risk models, with death as a competing event; differences were tested using Gray's test. Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs). Results A total of 110 patients were included. 53 patients received PTCy-based prophylaxis (43 PTCy/Tac/MMF, 1 PTCy/CSA/MMF, 9 PTCy/Siro/MMF), while 57 received non-PTCy regimens (54 Tac/MTX +/- 39 T-cell depletion, 2 CSA/MMF, 1 Tac/MMF). Median age at transplant was 63 (range: PTCy 40-76; others 38-74) years in both groups; 59 were male (58.5% PTCy vs 49.1% others). Median Karnofsky Performance Status (KPS) and HCT–Comorbidity Index (HCT-CI) in patients receiving PTCy vs non-PTCy were 90 vs 80 and 1 vs 3, respectively. Conditioning intensity was similar: 22.6% myeloablative vs 21.7%, and 77.4% reduced-intensity vs 76.7% in PTCy and non-PTCy, respectively (p=1.000). Stem cell source was peripheral blood in all patients except one in the non-PTCy group who received bone marrow. 58 patients had primary MF (54.7% PTCy vs 50.9% others), and 52 had secondary MF (45.3% PTCy vs 49.1% others), including essential thrombocythemia (28.3% PTCy vs 31.6% others), polycythemia vera (17.0% vs 15.8%), and MPN-NOS (0% vs 1.8%). Median follow-up was 26.2 months (95% CI: 20.7-52.7) in the PTCy and 60.6 months (95% CI: 53.1-70.6) in the non-PTCy cohort. CD3 and CD33 donor chimerism ≥95% at day +100 was 66.7% and 86.7% in PTCy vs 63.6% and 92.7% in others, respectively (p=0.50); day +100 driver molecular mutations were present in 32.1% of PTCy and 32.0% of others (p>0.99). Rates of acute GVHD grades ≥2 and ≥3 were not statistically significant, in the PTCy group (37.7% vs 49.1% p=0.229 and 17.0% vs 22.8% p=0.445, respectively). Chronic GVHD (any grade) occurred in 42.3% of PTCy vs 38.2% of others (p=0.664), while moderate-to-severe cGVHD was lower with PTCy (21.2% vs 27.3% p=0.461). Platelet engraftment was significantly delayed in the PTCy group (median 33 vs 21 days, p=0.030). Median time to neutrophil engraftment was also delayed in the PTCy group (20 vs 17 days, adjusted p=0.025). Age-adjusted HR for time to platelet engraftment was 0.60 (95% CI: 0.41–0.90; p=0.014), and for neutrophil engraftment 0.65 (95% CI: 0.44–0.95; p=0.025), indicating significantly delayed hematopoietic recovery with PTCy. Graft failure occurred in 9.4% vs 5.3% (p = 0.48); primary 7.5% vs 3.5%, secondary 1.9% vs 1.8% in PTCy vs non-PTCy groups, respectively. Relapse or progression occurred in 11.3% of PTCy vs 17.5% of others (p=0.355); four patients in the non-PTCy group progressed to AML post-transplant, versus none in the PTCy group (p=0.119). 1-year TRM was 22.6% in the PTCy group and 14.0% in the non-PTCy group, p = 0.324. Median OS was 72.8 months in the PTCy group (95% CI: 49.9 months, upper limit not estimable [NE]) and 93.4 months in the non-PTCy group (95% CI: 48.5 months, upper limit NE), although the difference was not statistically significant (p=0.739). After adjusting for age and HCT-CI, there were no significant differences in PFS (adjusted HR 1.37; 95% CI: 0.73–2.56; p=0.331) or OS (adjusted HR 1.27; 95% CI: 0.64–2.51; p=0.498). Conclusions In myelofibrosis patients undergoing allo-HCT, PTCy-based GVHD prophylaxis showed similar rates of grade ≥2 acute and moderate-severe chronic GVHD compared to non-PTCy regimens. Engraftment was significantly delayed, while OS and PFS were comparable. PTCy appears to be a safe and viable alternative to CNI-based prophylaxis.