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Brexucabtagene autoleucel (brexu-cel), a CD28-costimulated CD19-targeted chimeric antigen receptor T cell (CART19) product, was FDA-approved in 2020 after demonstrating remarkable efficacy in the pivotal ZUMA-2 trial of patients with mantle cell lymphoma (MCL). However, despite the impressive initial activity of CART19 cell therapy in MCL, most patients relapse within the first 3 years following treatment. Myeloid cells, such as monocytes and macrophages, have been demonstrated to be major inhibitors of other immune cells, including T cells. Growing evidence shows that monocytes and macrophages contribute to CART cell failure, although the exact mechanisms are not fully understood. To better understand the mechanisms contributing to CART treatment resistance in MCL, we first utilized brexu-cel products from patients with MCL on the ZUMA-2 trial to uncover their transcriptomic features by single cell RNA sequencing (scRNAseq) analysis. To understand if myeloid cells had negative impacts on clinical outcomes, we then analyzed autologous baseline peripheral blood mononuclear cell (PBMC) samples by scRNAseq. Our analyses of the brexu-cel samples revealed reduced response to IL-1β and its downstream signaling pathway as well as impaired T cell functions in non-responders. Transcriptomic analyses of the autologous baseline monocyte populations showed downregulation of IL-1β production and its associated pathways as well as upregulation of M2 phenotype-associated genes and IL-1 receptor antagonist (IL-1ra) in non-responder monocytes, implying a potential role of myeloid cells in CART resistance through impairment of IL-1 signaling in brexu-cel products. To validate our findings from the ZUMA-2 samples, we further studied the interactions between macrophages, MCL cells, and CART19 cells in preclinical models. First, CD28-costimulated CART19 cells generated from healthy donors were cocultured with JeKo-1, a CD19+ MCL cell line, and freshly isolated monocytes or ex vivo differentiated M2-like macrophages. M2-like macrophages were generated by incubating fresh monocytes with rhGM-CSF followed by coculturing with JeKo-1. CART19 antigen-specific proliferation was significantly inhibited by M2-like macrophages but not fresh monocytes (JeKo-1+CART19 vs JeKo-1+M2+CART19, p=0.00503). Transwell assays indicated that suppression by M2-like macrophages was contact-independent. Cytokine profile analysis of coculture supernatants showed significant elevation of IL-1ra in M2-like macrophage cocultures (JeKo-1+Mono+CART19 vs JeKo-1+M2+CART19, p=0.0292). This led us to hypothesize that M2-like macrophages inhibit CART19 by secreting IL-1ra to block IL-1 signaling in CART19. To test this hypothesis, we interrogated the role of IL-1ra in CART19. CART19 + JeKo-1 cocultures were supplemented with IL-1β + IL-1ra or IL-1β + IL-1ra + IL-1ra neutralizing antibody (neuAb). CART19 proliferation was improved by IL-1β (vehicle control vs IL-1β, p<0.0001). IL-1ra inhibited IL-1β-dependent CART19 proliferation (IL-1β vs IL-1β+IL1ra, p=0.0006), which was restored by IL-1ra neutralization (IL-1β+IL-1ra vs IL-1β+IL-1ra+IL-1ra neuAb, p=0.0215). Next, we assessed the impact of IL-1ra on CART functions in mouse MCL xenografts in the presence of M2-like macrophages. NOD-SCID-γ-/- (NSG) mice were subcutaneously injected with 0.5 million of human macrophages and 1 million of luciferase+ JeKo-1. Mice were then randomized once tumor engraftment was confirmed by bioluminescence imaging (BLI), followed by treatment with 2 million CART19 with 10 mg/kg IL-1ra neuAb or control IgG for 3 weeks. Combination of CART19 cells and IL-1ra neuAb led to improved antitumor activity based on BLI measurements compared to control IgG (IL-1ra neuAb vs control IgG, p=0.0058). Additionally, expression of IL-1RI, receptor of IL-1β and IL-1ra, was measured on T cells after coculturing CART19, JeKo-1, and M2-like macrophages. M2-like macrophages downregulated IL-1RI expression on CART cells, which might potentially desensitize CART response to IL-1β, resulting in further suppression in CART proliferation (JeKo-1+M2+CART19 vs JeKo-1+CART19, p=0.001). Overall, our study elucidates a potential mechanism of IL-1 pathway modulation mediated by myeloid cells in contributing to CART19 failure in MCL.

Introduction: Based on a donor versus no-donor analysis, UKALLXII/E2993 showed a survival benefit for adults with acute lymphoblastic leukemia (ALL) who underwent allogeneic hematopoietic cell transplantation (alloHCT) in first complete remission (CR1) compared to consolidation/maintenance chemotherapy alone. The follow-up phase 3 E1910 trial (NCT02003222) randomized BCR::ABL1-negative B-lineage ALL patients (pts) aged 30-70 years in measurable residual disease (MRD)-negative CR1 after intensification to conventional chemotherapy (CC) +/- blinatumomab (blin) and demonstrated significantly improved overall survival (OS) with blin (Litzow, NEJM 2024). The current exploratory subgroup analysis evaluates outcomes of MRD-negative pts randomized on E1910 who underwent alloHCT on trial. Methods: Among pts enrolled on E1910, pts in MRD-negative CR1 by 6-color flow cytometry after intensification who were randomized to CC +/- blin and subsequently underwent alloHCT were identified. We compared baseline characteristics, MRD status post induction, relapse-free survival (RFS) and OS using the Kaplan-Meier method and the two-sided log-rank test and Cox model. A multivariable analysis was performed with alloHCT included as a time-varying covariate as well as a landmark analysis comparing the outcome of pts with unfavorable risk on the CC + blin arm who underwent alloHCT versus those who did not. Results: Of 224 MRD-negative randomized pts, 44 underwent alloHCT on trial: 22 in each arm. The median time from randomization to transplant was 3.2 months (mos). The median follow-up from initial registration was 57.8 mos. Baseline demographics including age (median 55 years), gender (53% male), race (89% white) and ethnicity (89% non-Hispanic/Latino) were equally distributed. Compared to CC + blin, the median peripheral blood white cell (WBC) count and blast percentage at diagnosis were higher in the CC arm at 6,640 vs 3,740/uL and 55 vs 9%, respectively, while median marrow blast percentage and overall unfavorable risk as defined in E1910 (55% vs 64%) were similar. Of the 44 MRD-negative pts who proceeded to alloHCT on study, 77% in the CC arm and 64% in the CC+ blin arm were MRD-negative after induction. Myeloablative conditioning was given to the majority of pts (68% CC arm and 73% CC+blin arm) and the most common graft versus host disease prophylaxis was tacrolimus-based on both arms. Among the 44 pts who underwent alloHCT, the observed hazard ratio (HR) comparing relative risk of death between pts randomized to CC+blin or CC only was 0.59 (95% CI: 0.12-2.11) with a 3-year OS rate of 82% versus 71% and the HR comparing relative risk of relapse/death was 0.52 (CI: 0.15-1.79) with a 3-year RFS rate of 82% versus 67%. For patients with unfavorable risk, 3-year OS and 3-year RFS in each treatment arm were both 71% versus 65%. Among 50 pts with unfavorable risk in MRD-negative CR after intensification who were randomized to CC + blin, a landmark analysis performed at 5 mos post randomization showed 3-year OS and RFS rates of 71% versus 90% and 71% versus 86% between the 14 pts who underwent alloHCT and those who did not, respectively. Receipt of alloHCT was a time-varying covariate in a multivariable analysis with gender, WBC count, platelets, hemoglobin, peripheral blood blasts, bone marrow blasts, performance status, and combined molecular risk category. Age, CD20 status, rituximab use, and intention to receive alloHCT were used as stratification factors. In the entire cohort of MRD-negative pts who were randomized, there was a significant association between improved OS and the receipt of CC+blin vs CC alone (HR 0.46, 95% CI: 0.26 - 0.82; p=0.009), better performance status of 0-1 vs ≥2 and favorable vs unfavorable risk ALL. In contrast, the receipt of alloHCT had no significant effect on OS (HR 1.00, 95% CI: 0.49 - 2.01). Conclusions: Within the constraints of small numbers, this exploratory subgroup analysis demonstrates that in pts with newly diagnosed BCR::ABL1-negative B-ALL treated on E1910 who achieved MRD-negativity after intensification, alloHCT outcomes did not appear to be different with or without blin in consolidation. In a multivariate analysis of all MRD-negative pts, receipt of blin but not alloHCT was associated with improved OS. Further investigation is warranted to characterize the relative benefit of blinatumomab in pts receiving alloHCT in frontline consolidation.

Introduction Patients (pts) with relapsed/refractory (R/R) myelodysplastic syndromes (MDS) have a poor prognosis and, until recently, lacked therapeutic options. Ivosidenib (IVO) is an oral, targeted, small-molecule inhibitor of mIDH1. In October 2023, IVO was granted FDA approval for the treatment of adult pts with mIDH1 R/R MDS on the basis of results from the pivotal AG120-C-001 MDS substudy (NCT02074839); IVO showed an acceptable safety profile and induced durable remissions, with a high rate (38.9%) of complete remissions (CR) per International Working Group (IWG) 2006 criteria (DiNardo et al. Blood Adv 2024; bloodadvances.2023012302.). Response criteria evolve to better reflect clinical benefit in specific pt populations and reduce interobserver variability. The updated IWG 2023 criteria for higher-risk MDS lowered the hemoglobin threshold for CR, added response categories for pts with <5% blasts or limited count recovery, and eliminated the marrow CR (mCR) category. Herein we analyze responses, transfusion independence (TI), and survival outcomes of pts treated with IVO according to IWG 2023 criteria. In addition, responses assessed per IWG 2023 and IWG 2006 criteria are compared. Methods Pts with mIDH1 R/R MDS who had received prior SOC therapy were eligible. Oral IVO 500 mg was administered daily on days 1-28 of 28-day cycles. Responses were assessed per IWG 2023 criteria, and a composite CR (CRc) category was included in the analysis, which comprises all CR categories: CR + CR equivalent (CRe) + CR with limited count recovery (CRL) + CR with partial hematologic recovery (CRh). Overall response rate (ORR) was defined as CR + mCR + partial remission (PR) per IWG 2006 criteria, and as CRc + PR + hematologic improvement (HI) per IWG 2023 criteria. For TI analysis, non-CRc was defined as HI + PR + no response (NR)/not evaluable + progressive disease. TI was defined as requiring no transfusion for ≥56 days. Results In total, 19 pts were enrolled (median age: 73 yr; prior hypomethylating therapy: 78.9%) and data from 18 efficacy-evaluable pts were analyzed. CR + PR rate (primary endpoint) per IWG 2006 was 38.9%, with all 7 (38.9%) responders having CR. CRc + PR rate per IWG 2023 was 66.7% (n=12), with all responders having CRc, including 5 (27.8%) pts with CR, 3 (16.7%) with CRe, and 4 (22.2%) with CRL (CR unilineage [CRLuni], n=2 [11.1%]; CR bilineage [CRLbi], n=2 [11.1%]); no pt had CRh or PR. ORR was 83.3% per IWG 2006, with 7 (38.9%) pts having CR and 8 (44.4%) mCR; 4 (22.2%) pts with mCR had HI. Per IWG 2023 criteria, the ORR was 72.2%, with 12 (66.7%) pts having CRc and 1 (5.6%) HI with neutrophil response. The 8 mCR per IWG 2006 criteria were reclassified as 1 CR, 4 CRL (2 CRLuni and 2 CRLbi), 1 HI, and 2 NR per IWG 2023. Median time to CRc was 1.58 mo. Median duration of CRc was not reached and Kaplan-Meier (KM) estimates at 3, 6, and 12 mo were 90.9%, 81.8%, and 68.2%, respectively. Five (CRc group n=4; non-CRc group n=1) of 7 (71.4%) and 3 (CRc, n=1; non-CRc, n=2) of 4 pts requiring red blood cell (RBC) and platelet transfusion at baseline, respectively, had TI. Median time to any (RBC/platelet) TI was 2.64 and 2.43 mo for pts with CRc and non-CRc, respectively. Moreover, 10 of 12 (83.3%) pts with CRc and 3 of 6 (50%) with non-CRc had or maintained TI during the study. Median duration of TI was not reached and KM estimates at 3 and 6 mo were 90.0% and 65.6%, respectively, for pts with CRc and 100% and 66.7% for non-CRc. Median event-free survival (EFS) was not reached for pts with CRc (n=12) or NR (n=5), and KM estimates at 1 yr were 68.2% and 53.3%, respectively. Median overall survival (OS) was not reached for pts with CRc and was 16.5 mo for pts with NR. For pts with CRc, OS KM estimates at 1, 3, and 5 yr were 90.9%, 51.1%, and 51.1%, respectively. For pts with NR, OS KM estimates were 75% at 1 yr and not estimable at 3 and 5 yr. For the pt with HI, the EFS estimate at 1 yr was 100% and OS estimates were 100% at 1, 3, and 5 yr. Conclusions IVO resulted in a high ORR (72.2%) according to IWG 2023 criteria, including a 66.7% CRc rate, despite the removal of the mCR category. Of 8 mCR per IWG 2006 criteria, 5 (62.5%) were reclassified as CRc per IWG 2023 criteria. By eliminating mCR and assessing response in a high-risk population with <5% blasts, IWG 2023 criteria accurately capture the clinical benefit of IVO in R/R MDS. While comparison of survival outcomes between IWG 2006 and IWG 2023 is limited by the small sample size, a similar trend with response-dependent EFS and OS outcomes was observed.

Background : Rituximab is a monoclonal antibody that targets CD20 and can significantly improve the prognosis of patients with CD20-positive B-cell non-Hodgkin lymphoma (B-NHL). Nonetheless, a significant number of patients experience disease progression or relapse post-rituximab therapy. CD19-chimeric antigen receptor (CAR) T cells have demonstrated remarkable efficacy in B-NHL treatment. However, few studies have focused on the efficacy and safety of CD20 CAR-T cells in rituximab-refractory/relapsed (R/R) B-NHL patients, particularly those treated with rituximab for a short time. Here, we conducted a prospective study, aimed to assess the long-term remission and survival in patients with rituximab-R/R B-NHL after treatment with U16 (CD20 CAR-T cells). Methods : This first-in-human study is an open-label, single center investigator-initiated trial (IIT) to determine the safety and efficacy of CD20 CAR-T in R/R B-NHL after previous rituximab treatment failure (no. ChiCTR2000036350). CD20 CAR-T was administered at a target dose of 1.0×107 CAR-T cells/kg after a 3-day conditioning chemotherapy with fludarabine and cyclophosphamide. The primary objective was to assess the safety and tolerability of CD20 CAR-T. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were graded according to ASTCT 2019 criteria. The secondary objectives were to evaluate efficacy and pharmacokinetics (PK). Response was assessed per Lugano 2014 criteria. Results:A total of 16 patients with R/R B-NHL were enrolled.The median age was 49 years (range, 28-66). Median number of prior lines of therapy was 3 (range, 2-5). All patients had received rituximab therapy; of these, 9 had done so within the 3 months before CAR-T infusion. CRS occurred in all patients, with 11 patients (68.75%) experiencing grade 1 or 2 CRS and 5 patients (31.25%) experiencing grade 3 CRS. No patient developed grade 4 CRS , and only one patient had ICANS.The most common grade 3 or higher adverse events observed after infusion included leukopenia (93.3%), anemia (40%) and thrombocytopenia (60%). An overall response rate of 100% was observed among enrolled patients, with 11 patients (68.75%) achieving complete remission(CR) and 5 patients (32.25%) achieving partial remission(PR) within 3 months. The median follow-up time was 11.7 months(range 0.69-47.47). The median overall survival was not reached, and the median progression-free survival was 14.5 months. 9 patients remained CR or PR for 12 months, with 7 of them continuing in CR for up to 24 months. The pharmacokinetics of CD20 CAR-T cells were assessed using quantitative PCR to determine the expansion and persistence ability. Peak CAR amplification were detected 7-14 days after infusin. Patients 1, 2 and 4 achieved long-term remission, and persistent positive CAR-T cell copy numbers were detected for 15 months, 30 months and 26 months, respectively. However, patients 7, 8 and 12 relapsed within 3 months, and the CAR-T cell copies of all three patients were reduced to fewer than 1×103 copies/μg of DNA within 3 months. The qPCR results indicated that the maintenance of efficacy was closely related to the persistence of CAR-T cells. Notably, patients who received rituximab less than 3 months before CAR-T infusion had a poorer prognosis, with higher relapse rates (77.8% vs. 28.6%) and shorter progression-free survival, regardless of the degree of response. Conclusion : Long-term follow-up demonstrated that CD20 CAR-T therapy can produce a deep and durable response with a favorable safety profile in patients with rituximab-refractory/relapsed B-NHL. Notably, patients who had received rituximab within 3 months had a poorer prognosis.

Introduction Knowledge of epidemiologic risk factors, clonal changes associated with MDS development from precursor states, and evolution from one MDS state to another (lower- (LR) or higher-risk (HR) disease or leukemia (AML)) are largely limited to retrospective studies, which may not reflect the true MDS spectrum. The MDS NHS is an established prospective cohort of patients (pts) with suspected MDS enrolled at diverse US sites. Extensive clinical data and biospecimens are collected at baseline and throughout follow-up (F/U), in real time, as pts are followed for life. Here, we assess rates and potential predictors of progression providing a foundation for precise stratification across the MDS spectrum, which may ultimately guide intervention. Methods At baseline, all MDS NHS pts have central pathology review and those assigned to MDS, MDS/MPN overlap, AML<30% blasts, or at-risk of MDS (AR-MDS: CCUS and other at-risk) are followed prospectively. We compared AR-MDS with LR-MDS (MDS and MDS/MPN overlap with IPSS-R ≤ 3.5) and HR-MDS (MDS and MDS/MPN overlap with IPSS-R > 3.5). We defined disease progression as any F/U diagnosis of worsening disease or documented disease-related death. Rates of disease progression were compared between groups using survival analysis methods for cumulative incidence incorporating non-disease death as a competing risk. Associations between progression and predictor variables were explored using univariate tests of association and multivariable survival (Cox regression) models for time-to-progression and logistic models for probability of progression (yes/no). Results The MDS NHS enrolled 2051 pts during June 2016-February 2024, with 54% (1111, above categories) followed prospectively. Median F/U is 1.7 yrs (IQR: 0.8-3.1 yrs, max: 7.9 yrs). For the current analysis, 582 MDS and 505 AR-MDS pts were included. Compared to AR-MDS, MDS patients were more often male (70% v 61%, p<0.01), older (median age: 75 v 72 years, p<0.01), and had lower baseline hemoglobin (median: 10.1 v 11.9 g/dL, p<0.001), platelets (median: 124 x109 v 146 x109 cells/L, p<0.001), and absolute neutrophil counts (median: 1.9 x109 vs 2.8 x109 cells/L, p<0.001). F/U time was similar among AR-MDS and MDS (median: 1.9 vs 1.6 yrs), with both groups having a 75th percentile of 3 yrs and maximum of 7 yrs. A total of 331 deaths were observed (30%), with 145 (44%) of these due to causes related to MDS (myeloid disease and/or cardiovascular disease). Overall, 18.5% had disease progression, with annual rates of 8% (MDS) and 2% (AR-MDS) (p<0.01). Among HR-MDS, progression rates were greatest in the 1st year following diagnosis (33%) and declined thereafter, whereas progression rates remained between 5-8% for LR-MDS and 1-3% for AR-MDS over 5 yrs of F/U. AR-MDS had similar rates of progression within the first 3 yrs from diagnosis as MDS with the lowest IPSS-R category. Among AR-MDS, low hemoglobin (hazard ratio, HR [95% CI]=3.2 [1.4-7.3], p<0.01) was significantly associated with progression. Among MDS, low hemoglobin (HR=4.0 [2.2-7.0], p<0.001), low platelet count (HR=3.1 [1.7-5.6], p<0.001) and higher numbers of mutations (HR=1.13 [1.0-1.2], p<0.01) were significantly associated with progression. Due to the low rate of progression in AR-MDS, meaningful comparisons of mutations could not be completed. In MDS, univariate analyses showed that somatic mutation prevalence in gene pathways for transcription, cell cycle and RAS signaling, and in genes TP53, BCOR, SF3B1, DDX41, PTPN11, SETBP1, and JAK2 were significantly associated with the probability of progression (p<0.05 in all). In multivariable models, adjusting for patient age, sex, and MDS risk level, the probability of progression (PP) was significantly higher among those with vs without somatic mutations in BCOR (PP=63% vs 29%, p=0.004), PTPN11 (PP=67% vs 29%, p=0.009), SETBP1 (PP=61% vs 30%, p=0.02), JAK2 (PP=59% vs 30%, p=0.02), DDX41 (PP=56% vs 30%, p=0.03) and TP53 (PP=43% vs 29%, p=0.04). Conclusions In this large prospective cohort of MDS and pts at risk for MDS, the annual rate of any disease progression was 8% among MDS and 2% among AR-MDS, lower than some retrospective series. Specific cytopenias and genetic factors associated with progression were identified. The MDS NHS provides an incomparable opportunity to address the critical clinical challenges of management and prevention of MDS progression across its spectrum.

Introduction: Myelodysplastic syndromes (MDS) occur due to the acquisition of mutational events over time. Tobacco smoking is a risk factor for MDS and has been associated with distinct genetic mutations in solid cancers. We investigated the association between smoking intensity and duration and the number and types of genetic mutations in MDS using a large prospective cohort. Methods: The prospective NHLBI/NCI National MDS Natural History Study includes individuals with suspected or recently diagnosed MDS enrolled between June 2016-August 2023. Patient (Pt) bone marrow samples underwent central pathology review, resulting in diagnoses including MDS, MDS/myeloproliferative neoplasm overlap (MDS/MPN), or precursor conditions, such as clonal cytopenia of undetermined significance (CCUS). Self-reported smoking data were collected at enrollment. Smoking intensity (i.e., light, medium, and heavy) was defined per CDC definitions. Included mutations were those manually annotated to be pathogenic for MDS. Mutation frequency and prevalence, as well as associations with smoking history and other key covariates, were assessed using univariate tests of association and multivariable regression models for counts and proportions. Rates of disease progression were compared between groups using survival analysis methods for cumulative incidence incorporating non-disease death as a competing risk. Results: Of 1898 evaluable pts, 52% (N=979) had a history of cigarette smoking [MDS: 58% (252/436), MDS/MPN: 57% (52/91), CCUS: 57% (230/405)], and 18% still smoked at diagnosis. The mean ± SD cigarettes per day was 15.8 ± 12.5 and the mean ± SD smoking years was 29.8 ± 16.9 years. Compared to non-smokers, smokers were more often males (68% v 54%, p<0.001) in the 70-79 year age group (45% v 34%, p<0.001). Similar proportions of those with and without a smoking history had MDS (41% v 37%, respectively). Within MDS, there was no association between smoking and MDS prognostic risk per revised international prognostic scoring system. Compared to light smokers [1-10 pack-years (PY)], heavy smokers (30+ PY) were more often male (81% v 62%, p<0.001) and had higher rates of cardiovascular disease (38% v 20%, p<0.001). In univariate analyses, smokers and non-smokers had similar numbers of mutations (mean ± SD: 2.0 ± 2.7 in both groups). Pts with CCUS had the least number of mutations (1.5 ± 1.2), followed by MDS (2.3 ± 1.8), and MDS/MPN overlap (3.3 ± 1.8). Within disease groups, smokers and non-smokers had similar numbers of mutations. Mutation prevalence was higher among smokers v non-smokers in gene pathways for chromatin modification (15% v 11%, p<0.01) and RNA splicing (26% v 19%, p<0.001) and for individual genes ASXL1 (12% v 8%, p<0.01), SF3B1 (9% v 6%, p<0.05), U2AF1 (6% v 3%, p<0.05) and ZRSR2 (2% v 1%, p<0.05). In multivariable regression models, after adjustment for sex, age and disease group, smokers had significantly more mutations on average than non-smokers (2.0 v. 1.4, p=0.04). Moreover, the number of mutations increased significantly with PY smoked (p=0.006), and those at the 75th and 90th percentiles of PY had 1.8 and 3.5 times the number of mutations, respectively, compared to non-smokers, indicating a dose-response relationship. After adjustment, mutation prevalence increased with PY smoked in the gene pathways for chromatin modification and RNA splicing (p<0.03 for both) and for the genes ASXL1 and ETNK1 (p<0.05 in both cases). The five-year cumulative incidence of disease progression was significantly higher among long-term smokers compared to non-smokers/those with shorter smoking history (mean [95% CI] proportion progressed, 20+ years vs <20 years smoking: 27% [19%-36%] vs 18% [13%-24%], p < 0.05). Overall survival was significantly lower for smokers compared to non-smokers for CCUS pts [HR 1.91, 95% CI (1.03-3.55), p=0.04] but not for MDS [HR 1.21, 95% CI (0.53-1.30), p=0.41]. Conclusions: In this prospective, national cohort, tobacco smoking was associated with distinct genetic mutations related to MDS, suggesting smoking potentially contributes to its multi-step molecular pathogenesis. A dose-response relationship was also demonstrated, as was an association with progression and survival. Our data suggest that pts with a new MDS diagnosis who are also smokers should be counseled to stop smoking, as it appears to contribute to the acquisition of new genetic mutations that can lead to progression.

Introduction The pathogenic role of somatic non-coding (nc) single nucleotide variants (SNVs) is underexplored in multiple myeloma (MM) and additional characterization of these regions has the potential to provide significant new insights into disease progression. To investigate the role of ncSNVs and their relationship with MM pathogenesis, we have characterized a novel series of WGS from 294 cases of MGUS, SMM, and MM using computational tools optimized to identify functional driver SNVs in these regions. We hypothesize the ncSNVs that co-localize to sites of super-enhancers (SEs) active in plasma cells (PC) are sites of high functional impact SNVs and these mutations lead to the dysregulated expression of genes that should be silent at the terminally differentiated stage of PCs, providing a selective advantage that shapes the fitness of the MM genomic landscape. Methods We analyzed 294 high-coverage matched tumor/normal pairs (80x tumor and 40x normal) derived from 21 MGUS, 86 SMM, 167 NDMM and 40 RRMM. In addition to previously sequenced samples, newly sequenced patients were obtained from NYU Langone Health, Memorial Sloan Kettering Cancer Center, University of Alabama at Birmingham and University of Miami following IRB-approved informed consent. DNA was extracted from CD138+ purified bone marrow plasma cells using standard approaches. We used the MGP1000 (https://github.com/pblaney/mgp1000) to process sequencing data which employs a union-consensus mechanism for determining the final set of variants. We collected enhancer elements (E/SEs) active in GC B-cells, ABC-DLBCL and GBC-DLBCL (Bal, et al. Nature, 2022) and PC specific E/SEs (Loven, et al. Cell 2013). FunSeq2 was used to score ncSNVs. GRAM was used to predict how variants alter TF binding and gene expression in a subset of 6 cases with paired WGS in our series and will expand this analysis on a validation set of 263 NDMM and 93 RRMM cases from University-Hospital Heidelberg enrolled in the GMMG-HD6 clinical trial. Results We identified 1,952,232 high-quality SNVs with 18,199 (0.93%) accumulating in 280 focal sites we termed “mutationally enriched regions” or MERs. To discern SNVs in MERs with the highest potential for imparting a selective advantage, we clustered mutations based on the density of FunSeq2 impact scores which uses reference data contexts on sequence conservation, modification of transcription factor (TF) binding, and gene linkage to regulatory elements and network hubs from pan-cancer studies. We show that MERs are enriched for ncSNVs with high impact scores (mean=2.57) compared to random similarly-sized regions of the genome (Fisher's exact test P<9.7e-12, OR=10.10 [3.88-37.40]). The high impact ncSNVs (hi-ncSNVs) in MERs (n=220) account for 8.09% of all hi-ncSNVs and are present in 46.3% of cases (136/294) with some patients having up to 7. The proportion of cases carrying a MER hi-ncSNVs was similar across disease stages (MGUS=42.9%, SMM=46.5%, MM=40.7%, and RR=47.5%). Analysis of the VAF of MER hi-ncSNVs shows a minor shift towards more clonal versus subclonal mutations (53.6% vs 46.4% VAF>=0.25) suggesting some high impact mutations are acquired in the GC but additional hi-ncSNV are acquired later in PC development, providing evidence that hi-ncSNVs accumulate in MERs throughout disease progression. We mapped these hi-ncSNVs to associated genes then intersected the loci with E/SEs active in GCBs and PCs to determine their functional context. This approach identified 12 genes affected by hi-ncSNVs including the previously identified nc-drivers NEAT1, MIR142, ZCCHC7, and IGLL5 as well as the PC differentiation genes IRF8, BACH2, proliferation genes RHOH, SPRED2, known coding MM drivers CCND1, ZFP36L1, and chr1q genes BTG2 and CROCC. We predicted the effect of ncSNVs on expression through modulation of TF binding at this set of putative nc drivers in MM and identified a trend towards increase in expression of SPRED2, CCND1, NEAT1, and IGLL5 compared to non-mutated cases (P=0.089). We will present data on the validation of this set of genes on a larger set of data derived from the Heidelberg group. Conclusions We identified a set of 12 putative nc driver genes in MM that modify expression and have the potential to significantly alter the pathogenesis of MM by providing a selective survival advantage. We will present the impact of these by clinical stage and on outcome.

Introduction: Epcoritamab (Epcor) is a novel subcutaneous CD3xCD20 bispecific antibody (bsAb) that is currently approved as monotherapy for the treatment of adults with relapsed or refractory (R/R) large B-cell lymphoma after ≥2 systemic therapies. The combination of Epcor with standard treatment regimens has been shown to be safe and efficacious; Epcor in combination with gemcitabine and oxaliplatin (Epcor+GemOx) has provided deep and durable responses with favorable survival outcomes in a transplant-ineligible R/R diffuse large B-cell lymphoma (DLBCL) patient (pt) population, of which 99% were from the US and Europe (EPCORE NHL-2; NCT04663347). Another CD3xCD20 bsAb, intravenous glofitamab, has been studied in combination with gemcitabine and oxaliplatin (Glofi+GemOx) in the randomized STARGLO trial (NCT04408638) and demonstrated benefit over rituximab plus GemOx (R-GemOx), despite not demonstrating superiority over R-GemOx in patients from the US and Europe. In the absence of head-to-head data, this study used matching-adjusted indirect comparisons (MAICs) to assess the comparative efficacy of Epcor+GemOx vs R-GemOx and vs Glofi+GemOx. Methods: Individual pt-level data from EPCORE NHL-2 arm 5 and aggregated data from pts in each of the STARGLO arms were used to conduct an MAIC. Logistic propensity score models were used to weight Epcor+GemOx-treated pts to create matched cohorts with the R-GemOx and Glofi+GemOx arms separately. Weighting was conducted based on the distribution of baseline characteristics and prognostic factors such as age, sex, Eastern Cooperative Oncology Group performance status, previous therapies, and primary refractory status. Overall response rate (ORR), complete response (CR) rate, progression-free survival (PFS), and overall survival (OS) were compared for Epcor+GemOx vs R-GemOx, and vs Glofi+GemOx. Results: A total of 103 pts treated with Epcor+GemOx (median follow-up: 13.2 months) were compared to 91 pts treated with R-GemOx and 183 pts treated with Glofi+GemOx (median follow-up: 20.7 months), although differences in median follow-up time limited comparisons of longer-term survival outcomes. Match-adjustment mitigated differences in baseline characteristics across the 3 cohorts. After adjustment, Epcor+GemOx demonstrated a significant 44.8% advantage in ORR over R-GemOx (85.4% vs 40.7%), with a 110% increase in the likelihood of achieving a response (odds ratio [OR] 2.1; 95% CI 1.6-2.8; P<0.0001). Epcor+GemOx also demonstrated a significant 43.2% advantage in CR rate over R-GemOx (68.5% vs 25.3%), with a 170% increase in the likelihood of achieving a CR (OR 2.7; 95% CI 1.8-4.1; P<0.0001). With the current follow-up, Epcor+GemOx demonstrated superior PFS vs R-GemOx (hazard ratio [HR] 0.37; 95% CI 0.22-0.63; P<0.001), corresponding to a 63% reduction in the risk of progression. Median OS was not reached [NR] for Epcor+GemOx vs 13.9 months for R-GemOx, corresponding to a 43% reduction in the risk of mortality (HR 0.57 [95% CI 0.33-0.98]; P=0.04). After adjustment, Epcor+GemOx demonstrated a significant 15% advantage in ORR over Glofi+GemOx (83.3% vs 68.3%), with a 20% increase in the likelihood of achieving a response (OR 1.2; 95% CI 1.0-1.4; P=0.021). Epcor+GemOx demonstrated a trend toward higher CR rate than Glofi+GemOx (66.8% vs 58.5%; OR 1.1; 95% CI 0.90-1.5; P=0.277). Adjusted median PFS and OS for Epcor+GemOx, with limited follow-up and substantial censoring, was 12.9 months and NR, respectively. For Glofi+GemOx with longer follow-up, PFS and OS were 13.8 months and 25.6 months, respectively. Conclusions: Results show significantly superior efficacy for all outcomes with Epcor+GemOx vs R-GemOx from STARGLO. Epcor+GemOx also provided superior ORR and a trend toward higher CR rates vs Glofi+GemOx, indicating potential for better long-term efficacy outcomes. The Epcor+GemOx survival data are still maturing given shorter follow-up time, preventing a robust comparison of survival vs Glofi+GemOx. Findings support the efficacy of Epcor+GemOx as an alternative therapeutic regimen in transplant-ineligible patients with R/R DLBCL.

Introduction: Epcoritamab, a novel subcutaneously administered CD3xCD20 bispecific antibody (bsAb) being developed as a core therapy across several lymphoma subtypes, is currently approved for the treatment of adults with different types of R/R LBCL after ≥2 systemic therapies. The combination of epcoritamab with standard treatments has been shown to be safe and efficacious; epcoritamab in combination with gemcitabine and oxaliplatin (Epcor+GemOx) has provided deep and durable responses with favorable survival benefits in a transplant-ineligible R/R DLBCL study population, of which 99% was from the United States and Europe (EPCORE NHL-2; NCT04663347). The rituximab plus gemcitabine and oxaliplatin (R-GemOx) regimen has been a widely used treatment for patients with R/R DLBCL ineligible for transplant, albeit with suboptimal efficacy outcomes. In the absence of direct comparisons of these regimens, this study assessed the comparative efficacy of Epcor+GemOx vs R-GemOx in patients with R/R DLBCL ineligible for transplant. Methods: Individual patient-level data (IPD) from EPCORE NHL-2 arm 5 were compared to 2 sources of clinical practice data for patients with R/R DLBCL treated with R-GemOx: published data from Cazalles et al (2021) and IPD from the US-based COTA electronic health record database. The Cazalles study reports the results of a large retrospective analysis of patients with R/R DLBCL treated in 2 academic centers in France. The COTA database includes de-identified IPD with demographic and clinical information from numerous academic and community clinical sites in the US. For the comparison to Cazalles, logistic propensity score models were used to weight the Epcor+GemOx cohort to create match-adjusted distributions of baseline characteristics with the R-GemOx cohort in Cazalles. For the comparison to COTA, inverse probability of treatment weighting was employed to balance covariates between the Epcor+GemOx and R-GemOx cohorts. Analyses were restricted to chimeric antigen receptor T-cell therapy (CAR T)-naive patients from EPCORE NHL-2, as the comparator cohorts did not include patients treated with CAR T. Overall response rate (ORR), complete response (CR) rate, progression-free survival (PFS), and overall survival (OS) were compared for Epcor+GemOx vs R-GemOx. Results: A total of 74 patients treated with Epcor+GemOx (median follow-up: 13.2 months) were compared to 196 R-GemOx-treated patients from Cazalles et al (median follow-up: 22 months). After match-adjustment, Epcor+GemOx (ORR 86.8%) demonstrated significantly higher ORR, corresponding to a 48.5% advantage over R-GemOx (ORR 38.3%) with an odds ratio (OR) of 2.3 (95% CI 1.8-2.9; P<0.0001). Adjusted CR rate was also significantly higher with Epcor+GemOx vs R-GemOx (71.2% vs 32.7%; 38.6% difference; OR 2.2 [95% CI 1.6-3.0]; P<0.0001). Median PFS was significantly longer with Epcor+GemOx (26.7 months) vs R-GemOx (4.8 months; hazard ratio [HR] 0.38 [95% CI 0.22-0.67]; P<0.001). Median OS was not reached (NR) for Epcor+GemOx vs 10.0 months with R-GemOx (HR 0.54 [95% CI 0.29-1.0]; P=0.05), corresponding overall to a 62% reduction in the risk of a progression event and a 46% reduction in the risk of mortality with Epcor+GemOx vs R-GemOx. A total of 72 patients were treated with R-GemOx in COTA (median follow-up: 7.5 months) and compared to 74 Epcor+GemOx patients. After adjustment, ORR was significantly higher with Epcor+GemOx vs R-GemOx (88.5% vs 35.6%; OR 2.5 [95% CI 1.8-3.4]; P<0.0001). Adjusted CR rate was also significantly higher with Epcor+GemOx (63.9% vs 10.2%; OR 6.3 [95% CI 3.1-12.7]; P<0.0001). Adjusted median PFS was significantly longer with Epcor+GemOx (11.2 months) vs R-GemOx (2.4 months; HR 0.23 [95% CI 0.15-0.36]; P<0.0001). Adjusted median OS was also significantly longer with Epcor+GemOx (21.6 vs 8.3 months; HR 0.47 [95% CI 0.30-0.74]; P=0.002), corresponding overall to a 77% reduction in the risk of a progression event and a 53% reduction in the risk of mortality with Epcor+GemOx vs R-GemOx. Conclusions: In this indirect treatment comparison analysis,Epcor+GemOx provided significantly superior efficacy benefits in terms of ORR, CR, PFS, and OS vs standard-of-care R-GemOx. While subject to the limitations of comparisons outside of controlled trials, findings indicate the compelling efficacy of Epcor+GemOx as a novel therapeutic option for transplant-ineligible patients with R/R DLBCL.

Introduction MYD88 L265P mutations (MUT) are found in 90% of patients with Waldenstrom macroglobulinemia (WM) and lead to the activation of pro-survival signaling. Limited literature has demonstrated that patients with MYD88 wild-type (WT) WM have poorer responses to conventional therapies and a higher likelihood of histological transformation. Increasingly the role of non-coding genomics in lymphomagenesis has demonstrated importance and currently, the epigenetic landscape of MYD88 WT WM remains underexplored. This study utilized a multi-omics approach to assess DNA methylation in MYD88 WT WM compared to MYD88 MUT patients and controls. Methods Bone marrow samples were prospectively collected from 20 subjects [3 MYD88 WT/CXCR4 WT WM, 12 MYD88 MUT WM and 5 normal controls] and positive selection for CD19+ and/or CD138+ B cells was performed. The analysis focused on the comparison between MYD88 WT WM to normal controls and MYD88-WT to MUT WM. Genome-wide DNA methylation analysis was performed, and CpG methylation ratios were segmented into 200-bp regions. Differentially methylated regions (DMRs) were determined using a Q-value <0.05 and absolute methylation difference ≥10%. Next, RNA-seq data was interrogated and differentially expressed genes (log2fold change>0.5 or <-0.5, false discovery rate<0.05) with corresponding promoter hypo- or hypermethylation were assessed. Ingenuity Pathway Analysis was used to determine potentially epigenetically regulated pathways using a corrected p<0.05. Results Comparing MYD88 WT WM samples to controls, a statistically greater number of hypermethylated DMRs were observed across genomic regions (hyper- vs hypomethylated): promoter (29129 vs 6300), 3'untranslated region (UTR) (2068 vs 1551), 5'UTR (10169 vs 735), intron (30344 vs 24511), exon (2224 vs 6855), CpG island (30372 vs 1240) and CpG shore (14477 vs 5872) (all p<0.001). Next, mRNA analysis demonstrated that 214 genes were differentially up-/downregulated with concordant promoter hypo-/hypermethylation. On the assessment of promoter-methylation-based pathways, multiple pathways involved in cell signaling, proliferation, gene regulation, cytokine and immune signaling and metabolism were found to be deregulated. Most pathways were found to be negatively enriched in MYD88 WT patients compared to controls including several members of interleukin (IL) signaling (IL-2, IL-3, IL,7) and regulators of cell proliferation and signaling including mTOR, PI3K/AKT, and p53. Positive enrichment of the PTEN, FGFR3 and ERK/MAPK pathways were observed. Underlying multiple pathways was promoter hypermethylation with corresponding mRNA downregulation of AKT3 and PIK3CA. Furthermore, promoter hypomethylation with transcript upregulation of PTEN was observed. Next, in comparison of MYD88 WT to MUT samples, a statistically greater number of hypermethylated DMRs were observed across genomic regions (hyper- vs hypomethylated): promoter (24829 vs 2544), 3'UTR (3534 vs 378), 5'UTR (6111 vs 605), intron (52292 vs 5360), exon (21066 vs 2187), CpG island (18334 vs 1551) and CpG shore (16351 vs 1957) (all p<0.001). Assessing mRNA expression, 354 genes were up-/downregulated with concordant promoter hypo-/hypermethylation. Pathway analysis revealed positive enrichment of the mitotic G1 phase to G1/S transition pathway with upregulation of the CDK4, LYN, and PSMA6 transcripts in MYD88 WT compared to MUT samples. Further, negative enrichment of cell signaling regulators including the RHO GTPase family, IL pathways (IL-4, IL-8, IL-13, IL-17) and integrin signaling were found in MYD88 WT compared to MUT samples. Underlying multiple pathways were downregulation with promoter hypermethylation of BCL2, an important regulator of apoptosis. Conclusion Genome-wide methylation analysis of MYD88 WT WM revealed a unique DNA methylation profile, with potential epigenetic alteration of key oncogenic transcripts and pathways. The negative enrichment of cell signaling and cytokine/inflammatory pathways in MYD88 WT samples compared to controls and MYD88 MUT WM suggests an epigenetic mechanism for immune evasion and potentially underlies the reduced response to conventional WM-directed therapies. Overall, this study reveals that MYD88 WT WM is epigenetically distinct from MYD88 MUT WM and regulators such as methylation may underlie the unique clinical and phenotypic properties observed.