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Introduction CD19-directed CAR T-cell therapies are an important option for the management of relapsed/refractory (R/R) DLBCL. Studies suggest that ~50% of pts receiving CAR T-cell therapies will relapse within 6 months, with an estimated overall survival (OS) of only 5 months. Additionally, 25-35% of pts do not receive subsequent treatment, indicating a high unmet need. CD19 loss is a potential mechanism of resistance to CAR T-cell therapies; thus, treatments that target alternate B-cell antigens are an attractive option. Here, we report for the first time the primary analysis of the ELM-1 expansion cohort investigating the efficacy and safety of odronextamab, a CD20×CD3 bispecific antibody, in pts with R/R DLBCL progressing after CAR T-cell therapy (NCT02290951). Methods Pts aged ≥18 with DLBCL and disease progression after CAR T-cell therapy received intravenous odronextamab weekly in 21-day (D) cycles during Cycles (C) 1-4, with steroid prophylaxis and step-up dosing in C1 (described previously), followed by 160 mg on D 1, 8, and 15 of C2-4. After C4, odronextamab maintenance treatment continued at 320 mg Q2W until disease progression or unacceptable toxicity. Pts with complete response (CR) for ≥9 months transitioned to Q4W dosing. All pts received infection prophylaxis. The primary analysis was conducted when all pts had completed ≥9 months of follow-up. Primary endpoint was objective response rate (ORR), as assessed by independent central review (ICR) according to the Lugano classification. Key secondary endpoints included duration of response (DOR), progression-free survival (PFS), and OS. Exploratory endpoints included immune biomarker assessment. Results As of January 22, 2024, 60 pts were treated and evaluable for efficacy and safety, with median follow-up of 16.2 months. Prior CAR T-cell therapies were axi-cel (50%), tisa-cel (12%), liso-cel (10%), and not specified (28%). Median time since prior CAR T-cell therapy was 6.5 months (range 1.2-46.2). Median age was 63 years (range 27-82; aged ≥75 years: 10%), and 65% were male. Pts had received a median of 3 prior lines of therapies (range 2-9); 77% of pts were refractory to their last therapy, 77% were double refractory, and 72% were refractory to prior CAR T-cell therapy. 48% of pts relapsed within 90 D of CAR T-cell therapy, and 67% relapsed within 180 D. Of the 20 pts with available tumor biopsies at baseline, 10 were CD19(-) and only 2 were CD20(-). 92% of pts completed C1 and 52% completed ≥4 C of treatment. The median duration of treatment was 12 weeks (range 0.7-154.1). The ORR and CR rate by ICR were 48% and 32%, respectively, and were consistent across pts with high-risk features and across prior CAR T products. ORR in pts relapsing in ≤90 D was 21% (6/29) and in pts relapsing in ≤180 D was 33% (13/40). ORR was observed even in pts with low CD20. Median DOR was 14.8 months (95% CI 2.8-not estimable [NE]) and median duration of CR was not reached (NR) (95% CI 3.3-NE); the probability of maintaining CR for 24 months was 68%. Median PFS was 4.8 months (95% CI 2.6-5.4) and median OS was 10.2 months (95% CI 4.6-15.8). Median PFS and OS in complete responders was NR. T-cell counts increased at Week 14 and demonstrated a functional phenotype (CD69 expression and TEMRA count), which was confirmed by ex vivo stimulation. T-cell expansion was observed regardless of CAR T product or time from CAR T administration. The most common TEAE was CRS (any grade [G]: 48%; G1: 25%; G2: 23%; G≥3: 0%). G≥3 TEAEs occurred in 77% of pts (most common: neutropenia 17%, anemia 13%, and neutrophil and white blood cell count decrease 10% each). Five pts (8%) permanently discontinued odronextamab due to AEs (COVID-19, pneumonia, encephalopathy, epilepsy, and gait disturbance [n=1 each]). There was one treatment-related death (COVID-19 pneumonia). No cases of ICANS were reported. G≥3 infections occurred in 12 pts (20%); 2 were due to COVID-19. No cases of tumor flare or TLS were reported. Conclusions ELM-1 is the only study to prospectively evaluate efficacy and safety of a CD20×CD3 bispecific antibody in pts with R/R DLBCL progressing after CAR T-cell therapy. Odronextamab monotherapy was associated with encouraging efficacy and generally manageable safety in a setting with limited treatment options and historically dismal outcomes. Efficacy was observed even in pts relapsing in ≤90 D, supporting the potential of odronextamab as an accessible, off-the-shelf option in the post-CAR T setting.

Background: C10603/RATFIY was the first AML trial to show the benefit of adding a targeted agent to intensive chemotherapy for a specific genetically determined subset (Stone R et al, NEJM 2017). The addition of the multi-kinase inhibitor midostaurin (M) to chemotherapy in previously untreated adults with FLT3-mutant AML resulted in superior event-free (EFS) and overall survival (OS) compared to placebo (P) and led to the approval of this agent in combination therapy. Subsequently, additional targeted drugs including gilteritinib for relapsed/refractory FLT3-mutant AML and quizartinib plus chemotherapy in untreated adults with AML with FLT3-ITD disease have gained approval. Long-term follow-up after reporting of the primary endpoint, especially if met, is important in oncology. Objective: We report the EFS and OS data from C10603 using 10 years of follow up to determine the persistence of a midostaurin benefit and to assess the nature of late relapses or toxicity. Methods: C10603 enrolled 717 pts (360 on the M and 357 on the P arm; median age 47.8 years (range 18-61), 398 women (55.5%) of whom 51.7% were randomized to M and 59.4% to P (p=0.04), and 89% white) from 2011-2015 with previously untreated AML who had either a FLT3-TKD or ITD mutation with allelic ratio of >0.05 to receive daunorubicin/cytarabine (3+7) induction (one reinduction permitted) followed by up to 4 consolidation cycles with cytarabine 3 g/m2 every 12h on days 1, 3 and 5. M (50 mg bid) or P was given orally on days 8-22 of each chemotherapy cycle as well as daily during one year of single-agent maintenance. Allogeneic transplantation (alloHCT) was employed at investigator's discretion; study drug was not continued post-HCT. Pts stayed on their randomized arm and were not re-randomized prior to maintenance. Pts were followed for relapse and survival after the end of protocol therapy, regardless of subsequent therapy, for 10 years. Log-rank tests, Kaplan-Meier methods, and Cox proportional hazard models were used to evaluate the treatment effect in EFS and OS, as well as the alloHCT effect. All p values are two-sided. Results: We have completed the 10-year FU on this trial and data collection has concluded. The median EFS was 8.2 months (95% CI, 5.5-11.4) on the M arm compared with 3.0 months for P (95% CI, 1.9-6.0) with a HR of 0.79 (95% CI 0.67-0.94, p=0.0067). Among the 420 CR pts who achieved complete remission (CR) by the protocol specified time of 60 days, 253 have had an event (death in 69 and relapse in 184); these events were relatively equal on each arm. OS, the co-primary endpoint, remained marginally superior for those randomized to M compared to P; the 10-year OS estimate was 43.7% (95% CI, 38.7-49.3%) vs 38.6% (95% CI, 33.6-44.4%) (p= 0.0485). The hazard ratios for OS favored randomization to M in each key biological subgroup (FLT3-ITD low or high allelic ratio or FLT3-TKD), but smaller subsets precluded statistical significance. There was a 10-year OS benefit in favor of M in men (p=0.005), but not women (p=0.9). A total of 414 transplants were performed: only 5 in the latter half of the follow-up period. Transplantation in CR1 was highly beneficial overall (10-year OS, 56% vs 35.8% without transplantation, p=0.001). Among those transplanted in CR1, randomization to M was marginally better than P (61.5% vs 49%, p=.064). After censoring for alloHCT in CR1, there was an OS trend in favor of M (51.8% v 48.0%, p=0.102). In CR1 patients who were randomized to maintenance therapy, M reduced the cumulative incidence of relapse in ELN 2017 favorable and intermediate risk pts, but not in those with adverse risk disease (HR 0.71, 0.47, and 1.01, respectively); maintenance M had no effect on OS. Only 3 pts relapsed after 5 years (all randomized to M). 25 pts randomized to M vs 13 P pts died after 5 years of follow-up. 5 pts on each arm died of a new primary cancer whereas 17 M and 5 P pts were coded as having died from treatment-related causes. None of the 3 pts who relapsed after 4 years had spliceosome mutations at diagnosis; whereas 18% (21/117) patients pts who had relapsed earlier had spliceosome mutations at diagnosis (p=0.419). Conclusions: The EFS benefit of randomization to midostaurin vs placebo when added to chemotherapy was maintained over time, although the benefit for OS was diminished, likely due in part to aging. Patient and disease factors differed between early vs late relapses, which could suggest the use of alternative therapies during distinct therapeutic stages.

Abstract Aims Cardiogenic shock (CS) is a critical manifestation of severe cardiac dysfunction, necessitating precise evaluation of left ventricular (LV) function by transthoracic echocardiography. The prognostic value of global longitudinal strain (GLS) has not been examined in patients with CS. Therefore, we aimed to assess the prognostic significance of GLS in patients with CS. Methods and results This was a retrospective study of patients with CS from 2007 to 2018 who had a transthoracic echocardiography performed within 24 h of admission. GLS was measured, and conventional parameters were obtained. LV dysfunction was categorized by GLS: > 9.7% (Quartile 1), 7.0% < GLS ≤ 9.7% (Quartile 2), 5.0% < GLS ≤ 7.0% (Quartile 3), and ≤5.0% (Quartile 4). Outcomes included in-hospital and 1-year all-cause mortality. Among 623 patients with CS with the median LVEF of 31% [inter-quartile range (IQR): 24–41%] and the median GLS of 7.0% (IQR: 5.0–9.7%), in-hospital mortality was 29%. Mortality increased across GLS quartiles: Quartile 1: 17%; Quartile 2: 22%; Quartile 3: 35%; and Quartile 4: 42%. GLS remained the only independent echocardiographic predictor of in-hospital mortality after adjusting for clinical covariates (adjusted odds ratio: 1.23 per 1% decrease, 95% confidence interval: 1.04–1.46, P = 0.015). GLS independently predicted 1-year all-cause mortality (P < 0.001). The prognostic value of GLS was superior in cases with acute coronary syndrome. A classification and regression tree analysis identified GLS as the most important echocardiographic variable for predicting in-hospital mortality. Conclusion GLS independently predicted short- and long-term mortality in patients with CS, surpassing conventional echocardiographic parameters in prognostic value, supporting its potential role in risk stratification in this population.

Background: Monoclonal B-cell lymphocytosis (MBL) is a common premalignant condition that can be classified into chronic lymphocytic leukemia (CLL)-type (CD5, CD23, and CD20 co-expression), and non-CLL-type (CD5-negative) based on flow cytometry immunophenotypes. CLL-type MBL is relatively well characterized with increased risk of hematologic (especially lymphoid) malignancies, serious infections, and decreased response to vaccinations. However, the prevalence, genetic predispositions, and clinical consequences of non-CLL-type MBL remain to be fully elucidated. Herein, we report findings in non-CLL-type MBL in a large screening cohort. Methods: We screened 10,330 individuals (40 years or older with no prior history of hematologic cancers) for MBL with highly sensitive flow cytometry, in the Mayo Clinic Biobank, with patients recruited from primary care-based clinics. Individuals were genotyped by Regeneron Genetics. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI). Among those individuals residing in the 27 counties surrounding Rochester, Minnesota, we identified incident hematologic malignancies and melanomas using ICD codes and the Rochester Epidemiology Project, a population based medical records linkage system. All diagnoses were manually reviewed for confirmation. Cox regression was used to calculate hazard ratios (HR) and 95% CIs, adjusted for age and sex. Results: We identified 1,736 individuals with MBL and 8,341 individuals without MBL. Among those with MBL, 246 (14.2%) had non-CLL-type MBL as the major clone. The median age of non-CLL-type MBL was 77 years (range, 47-95). The prevalence of non-CLL-type MBL significantly increased with age, with 0.5% prevalence among those between 40 to 59 years of age, 2.3% prevalence among those between 60 and 79 years, and 7.8% prevalence in those 80 years of age or older. The prevalence of non-CLL-type MBL was significantly higher (P < .001) among males (3.1%) than females (2.0%). Using the genome-wide complex trait analysis tool, the heritability of non-CLL-type MBL was estimated to be ~26%, suggesting inherited genetics plays a role in etiology. To identify common inherited variants, we first evaluated the known CLL susceptibility variants, many of which also associated with CLL-type MBL. Among the 42 variants, none were statistically associated (all P > .05) with non-CLL-type MBL. We next conducted a genome-wide association study to identify novel variants, and the most significant variant resided in 10q26.3 (minor allele frequency [MAF]control = 0.7%, MAFMBL = 3.5%, OR = 6.4, 95% CI 3.6-11.3, P = 5.7 * 10-8). Among the 6,478 individuals (192 with non-CLL-type MBL and 6,286 without MBL) followed for incident hematologic malignancies, 36 developed lymphoid and 23 developed myeloid malignancies after a median of 4.2 years of follow up. Similar to CLL-type MBL, non-CLL-type MBL was associated with a 5.2-fold risk for lymphoid malignancies (95% CI 2.0-13.0, P < .001). Elevated but not significant risks were observed for myeloid malignancies (HR = 2.3, 95% CI 0.5-10.3, P = 0.27). The lymphoid malignancies developed by individuals with non-CLL-type MBL included diffuse large B-cell lymphoma, multiple myeloma, marginal zone lymphoma, and other low-grade lymphomas. We recently reported that individuals with CLL-type MBL are at higher risk for developing melanoma (HR = 1.9, 95% CI 1.3-2.8). Interestingly, non-CLL-type MBL had no evidence of an association with melanoma risk (HR = 0.4, 95% CI 0.1-1.8). We did not observe a significant difference in overall survival between individuals with non-CLL-type MBL vs those without MBL. Conclusions: In the largest screening cohort to date, we evaluated the etiology and clinical outcomes of non-CLL-type MBL, an understudied yet common condition that occurs in ~4 million adults in the United States. Non-CLL-type MBL is more common in men and older individuals, and evidence supports that inherited genetics plays an etiological role with 10q26.3 locus identified as a novel susceptibility locus. Individuals with non-CLL-type MBL had significantly increased risk of lymphoid malignancies, similar to CLL-type MBL, but, distinct from CLL-type MBL, no evidence of an increased risk of melanoma. Our study provides insights into the prevalence, genetic predispositions and clinical consequences of non-CLL-type MBL and how it differs from the classic CLL-type MBL.

Background: Polatuzumab vedotin (Pola) is an antibody drug conjugate targeting CD79b that incorporates the microtubule disrupting monomethyl auristatin E payload. Pola was approved in 2023 for the upfront treatment of diffuse large B cell lymphoma (DLBCL) in combination with rituximab, cyclophosphamide, doxorubicin, and prednisone (polaRCHP) based on the POLARIX trial. However, the activity of pola appears to vary based on DLBCL cell of origin (COO) subtype, with greater efficacy in activated B cell (ABC) DLBCL compared to germinal center B cell (GCB) DLBCL (Russler-Germain Blood 2023). When outcomes in POLARIX are stratified by COO, polaRCHP demonstrated progression free survival (PFS) and overall survival (OS) benefits over RCHOP in patients with ABC but not GCB subtype DLBCL (PFS HR 0.34 ABC vs 1.03 GCB, OS HR 0.27 ABC vs 1.64 GCB; Morschhauser ASH 2023 and FDA data). Most prospective studies of pola used gene expression to assess COO, which is not readily clinically available. This study aims to examine if COO subtype by Hans algorithm (based on CD10, BCL6, and MUM1 expression by immunohistochemistry) is predictive of pola responses and outcomes in patients with large B cell lymphoma (LBCL). Methods: We conducted a retrospective, multicenter observational study of adults with LBCL who received pola (monotherapy or in combination) from 2015-2024 with Hans algorithm COO data and response assessment available. Patients were stratified by receipt of pola in the frontline vs relapsed/refractory (R/R) setting. The primary endpoint was overall response rate (ORR) to pola-based treatment in GCB vs non-GCB subtypes. Secondary endpoints included complete response rate (CRR), PFS, and OS. For time to event endpoints, patients responding to pola who received CAR T or stem cell transplantation prior to progression were censored at time of cellular therapy. Demographics were summarized by descriptive statistics. Comparative and survival analyses used Chi squared/Fischer exact tests and Kaplan Meier analysis. Data cutoff was July 1, 2024. Results: 718 patients were included. Median follow-up was 15 months (interquartile range [IQR] 8-32). Median age at LBCL diagnosis was 66 years (IQR 56-74); 62% were men; 69 (10%) had double hit lymphoma (DHL); 129 (18%) had underlying low grade lymphoma. Pola was used in the frontline setting in 293 (41%) patients, of whom 139 (47%) had GCB vs 154 (53%) non-GCB COO. Of the 426 patients receiving pola for R/R LBCL (including one patient receiving pola retreatment), 224 (53%) had GCB vs 202 (47%) non-GCB COO. Among patients receiving pola-based regimens in the R/R setting (GCB vs non-GCB: pola monotherapy = 7% vs 4%, pola + R = 26% vs 26%, pola + BR = 55% vs 61%, pola + other = 12% vs 9%; p = 0.44), the ORR in GCB vs non-GCB LBCL was 36% vs 61% (p < 0.001), while CRR in GCB vs non-GCB was 17% vs 36% (p < 0.001). COO remained a significant component of logistic multivariate regression models of ORR (p < 0.001) and CRR (p < 0.001) when incorporating IPI at original LBCL diagnosis, histology, DHL status, and refractory status to frontline therapy. Despite this, no significant PFS or OS differences by COO were seen, potentially due to approximately 1/4 patients being censored due to receiving subsequent cellular therapy (e.g. CAR T) prior to progression. In patients receiving frontline pola-based regimens (of which 275 [94%] included an anthracycline), ORR and CRR were similar in GCB vs non-GCB (ORR 89% vs 88% p > 0.5; CRR 76% vs 77% p > 0.5). While PFS and OS were similar between COO groups in the frontline cohort, follow-up and cohort size were limited. Conclusion: Based on this real-world evidence, COO classification by Hans algorithm is a strong predictor of the activity of pola-containing therapy in R/R LBCL, with significantly higher ORR and CRR in patients with non-GCB compared to GCB COO LBCL. This aligns with the cumulative existing evidence. ORR and CRR to pola-containing therapy in the frontline setting did not differ significantly by COO subtype, but longer follow-up of larger cohorts is needed to clarify the predictive role of COO by Hans algorithm in this setting, especially considering the PFS advantage with polaRCHP in POLARIX was not associated with significant differences in ORR or CRR. Overall, clinicians should consider factoring COO subtype into treatment decisions regarding pola-containing regimens, and studies of pola-based therapies should stratify patients and report outcomes by COO subtype.

Background: ctDNA clearance after frontline DLBCL tx has shown strong prognostic value for favorable outcomes, with the potential to improve MRD-driven therapeutic strategies and establish MRD as a surrogate endpoint in future studies (Roschewski M, et al. Blood 2022; Goldstein J, et al. Blood 2023). However, further study is needed to evaluate the association of this noninvasive approach with efficacy outcomes after 2L LBCL tx. We previously reported ctDNA analysis after liso-cel infusion in TRANSFORM (NCT03575351; Stepan L, et al. Blood 2023;142[suppl 1]). Here, we describe the predictive value of pre-tx and on-tx ctDNA levels for durable clinical benefit (CR and event-free survival [EFS]) in both liso-cel and SOC arms from TRANSFORM (Kamdar M, et al. J Clin Oncol 2024), evaluating ctDNA as an earlier surrogate for conventional clinical outcomes. Methods: Baseline (prerandomization) and longitudinal ctDNA levels were assessed in randomized pts treated with liso-cel or SOC in TRANSFORM using the phased variant enrichment and detection sequencing assay (PhasED-Seq; Foresight Diagnostics). Phased variants were identified from baseline plasma samples for longitudinal ctDNA monitoring at multiple on-tx time points, as previously described (Stepan L, et al. Blood 2023;142[suppl 1]). Randomization was defined as study Day 1. Association of ctDNA levels with response per independent review committee using Lugano 2014 criteria and EFS was investigated at various predefined time points, including Day 43 (after 2 cycles of salvage immunochemotherapy for SOC; Day 15 after liso-cel infusion), Day 64 (after 3 cycles of salvage immunochemotherapy for SOC; 1 month after liso-cel infusion), and Day 126 (within 2 months after ASCT; 3 months after liso-cel infusion). To assess the surrogacy value of ctDNA, ctDNA-MRD dynamics and ctDNA clearance were investigated within both arms. Results: In pooled analyses combining the liso-cel and SOC arms, higher baseline ctDNA levels (above the median) were associated with shorter EFS (P = 0.05). Pts achieving Day 126 CR had substantial reductions in ctDNA burden vs baseline, while pts with PD or stable disease had persistently high ctDNA levels vs baseline. Achieving undetectable ctDNA at different time points was associated with significantly longer EFS in pooled analyses, observed as early as study visit Day 43, with the strongest association at Day 126. HR (95% CI) for inferior EFS was 3.0 (1.6-5.7) at Day 43, 3.8 (2.1-7.0) at Day 64, and 4.2 (2.3-7.7) at Day 126 in pts with detectable vs undetectable ctDNA. In the analysis by tx arm, consistent with the pooled analyses, ctDNA clearance was associated with EFS benefit at all measured time points with either liso-cel or SOC. Significantly more pts achieved undetectable ctDNA with liso-cel vs SOC during the study (39/63 [62%] vs 25/65 [38%], respectively; P = 0.013), consistent with superior EFS (primary endpoint) with liso-cel in TRANSFORM. All pts in the SOC arm with evaluable ctDNA at Day 126 (n = 28) had received high-dose chemotherapy (HDCT)/ASCT. However, pts with undetectable ctDNA in the liso-cel vs SOC arm had longer EFS at all predefined time points and had statistically longer EFS at Day 126 (SOC vs liso-cel: HR, 3.9 [95% CI, 1.4-10.6]), indicating a deeper and more durable response with liso-cel vs SOC. In pts with CR, ctDNA showed significant predictive value beyond the response assessment at all time points in the liso-cel arm with a HR (95% CI) of 3.8 (1.3-11.0) at Day 64 and 7.0 (2.0-24.3) at Day 126 for EFS in pts with detectable ctDNA vs undetectable ctDNA. Among pts in the SOC arm who experienced subsequent PD despite achieving CR (all received HDCT/ASCT) and undetectable ctDNA at Day 126, serial ctDNA assessment showed consistent reversion to detectable ctDNA at later time points. Conclusions: ctDNA data from TRANSFORM confirm the value of ctDNA as a biomarker for disease burden monitoring and early prediction of durable clinical benefit after 2L LBCL treatment. Furthermore, longitudinal ctDNA molecular response results agree with previously reported clinical efficacy data and confirm the superiority of liso-cel with deeper responses over the historical SOC in 2L LBCL. ctDNA may have a key role as a surrogate endpoint in future LBCL studies, including after CAR T cell therapies.

Background: Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) are known safety concerns following chimeric antigen receptor (CAR) T-cell therapy. Axi-cel, a CAR T-cell therapy approved in the US for adults with R/R LBCL after ≥ 1 line of prior therapy (2L+), has been administered in the outpatient setting, where a common cause for post-infusion hospital admissions were CAR T-cell-related toxicities (Furqan et al., 2024). Due to reimbursement policies in the US, patients at higher risk for safety events requiring inpatient care within 3 days of infusion may not be ideal candidates for outpatient care. We sought to identify what pre-infusion characteristics may put patients more at risk for developing early CRS and ICANS after axi-cel. Methods : Patients receiving axi-cel for R/R LBCL 2L+ between 01/2021−10/2023 registered in the Center for International Blood and Marrow Transplant Research (CIBMTR) observational database were potentially eligible for analysis. Patients with prior non-transplant cellular therapy or missing data for analysis were excluded. Primary endpoints were onset of early CRS and early ICANS, defined as an any grade event within 3 calendar days of axi-cel infusion (date of infusion is defined as Day 0 and onset of CRS/ICANS before the end of Day 3 is an early event). Early Grade ≥ 2 and early Grade ≥ 3 CRS and ICANS (onset of CRS/ICANS before the end of Day 3 and maximum Grade ≥ 2 and ≥ 3 per ASTCT Criteria) were also evaluated. Patient demographics, ECOG PS, comorbidities, disease characteristics at diagnosis and prior to infusion, line of therapy (LoT), lab assessments prior to infusion, and infusion-related attributes were evaluated by univariate screening and multivariable regression for development of early CRS or early ICANS. Results: A total of888 patients from 105 centers were included in the analysis. Median age was 63 years (45% ≥ 65 years) and 66% were male. At LBCL diagnosis, 22% of patients had a histological transformation. Prior to infusion, 5% of patients had ECOG PS ≥ 2 and 70% had at least 1 clinically significant comorbidity. Half (50%) of patients received axi-cel with 1 prior LoT (2L) and 10% of patients underwent a prior autologous hematopoietic cell transplant. Median time from leukapheresis to infusion was 30 days (interquartile range [IQR] 27−34). Bridging therapy of any type was administered in 59%, and systemic bridging therapy in 48%, of patients and 14% of patients were intended to be treated in the outpatient setting. Thirty percent of patients had chemo-sensitive disease prior to infusion. Median follow-up post-infusion was 12.3 months (range 3−38). Median time to onset of CRS was 4 days (IQR 2−6) and 84% of patients experienced CRS at any time. Early any grade (Grade ≥ 3) CRS was observed in 47% (3%) of patients. In the multivariate analysis of early any grade CRS, only prior LoT (≥ 2 vs 1) was associated with lower risk (OR 0.71; 95% CI 0.55−0.94), but this association was not seen in the analyses of early Grade ≥ 2 nor early Grade ≥ 3 CRS. Notably, 47% and 52% of patients with ≥ 2 vs 1 prior LoT, respectively, only experienced early Grade 1 CRS (defined as fever only). In the analysis of early Grade ≥ 3 CRS, only ECOG PS 0−1 was associated with lower risk vs patients with ECOG PS ≥ 2 (OR 0.17; 95% CI 0.06−0.48). Median time to onset of ICANS was 7 days (IQR 5−9) and 47% of patients experienced ICANS at any time. Early any grade (Grade ≥ 3) ICANS occurred in 9% (5%) of patients. After multivariate adjustment, age < 65 vs ≥ 65 (OR 0.38 [95% CI 0.23−0.62]) and 1 vs ≥ 2 prior LoT (OR 0.58 [95% CI 0.36−0.95]) were associated with lower risk of early any grade ICANS. Age < 65 vs ≥ 65 was also associated with lower risk of early Grade ≥ 3 ICANS (OR 0.31 [95% CI 0.15−0.61]), as was ECOG PS 0−1 vs ECOG PS ≥ 2 (OR 0.30 [95% CI 0.11−0.83]). Comorbidities were evaluated and no significant associations with early CRS nor early ICANS were found. Conclusions: This analysis of readily available clinical variables in a real-world contemporary cohort of patients treated with axi-cel demonstrates that younger patients and patients with better ECOG PS have lower risk of early CRS and early ICANS. Axi-cel in 2L setting, vs 3L+, is associated with lower risk of early any grade ICANS and comparable early Grade ≥ 2 CRS, but a higher risk of early fever. These results further enable a more informed decision of patient selection for physicians, which is critical for the success of outpatient administration.

Introduction: ELA026 is a first-in-class human monoclonal antibody directed against signal regulatory protein (SIRP)α/β1/γ and is under clinical investigation in secondary hemophagocytic lymphohistiocytosis (sHLH). sHLH is a life-threatening hyperinflammatory condition caused by failure to terminate the activation and proliferation of natural killer (NK), T cells and macrophages after an initial immune response. There are no approved therapies for sHLH. With a mortality rate of approximately 50% at 2 months (Lionel et al. 2023), malignancy-associated HLH (mHLH) is the deadliest subtype of sHLH. Cytotoxic, multi-agent chemotherapy (including etoposide) does not address the poor prognosis associated with mHLH (Xie et al. 2013). Directly targeting the pathogenic SIRP(+) myeloid cells and T lymphocytes represents a novel approach to resolving this severe hyperinflammatory condition. Methods: This is an open-label, single-arm, Phase 1b global multicenter study (NCT05416307) evaluating the safety, efficacy, pharmacokinetics, and pharmacodynamics of ELA026 in adult and pediatric patients with newly diagnosed and previously treated sHLH. The study is expanding enrollment to evaluate a fixed-dose regimen consisting of a priming phase of 0.1 mg/kg Day 1 and 0.3 mg/kg Days 2-4, followed by a maintenance phase of 0.5 mg/kg twice weekly beginning on Day 8. ELA026 is administered intravenously, with the option to transition to subcutaneous administration upon hospital discharge. The treatment period is 12 weeks with the option to extend in patients deriving ongoing clinical benefits. Enrollment in this cohort is restricted to frontline settings based on the experience that relapsed/refractory sHLH patients exhibited poor survival even with HLH disease control and died from complications related to severe baseline comorbidities. Response is evaluated using a modified HLH-2004 criteria (Locatelli et al. 2020) and survival is calculated from the time of HLH diagnosis. All patients receive dexamethasone as background therapy and premedication initially. Patients with mHLH may also receive cancer-directed therapies concurrently. Primary pharmacodynamic (PD) effects (monocyte and lymphocyte reduction) and secondary PD effects (C-reactive protein [CRP], ferritin, and sCD25 reduction) were best evaluated and attributed to ELA026 during windows of treatment without concurrent chemotherapy effects. Results: As of July 15, 2024, 12 treatment-naïve mHLH patients have enrolled in all cohorts of the study, with a median age of 47 years (range 21-78). The following malignancies were represented: 7 T-cell lymphoma, 2 DLBCL, 1 AML, 1 Hodgkin lymphoma, and 1 T-cell ALL. In this group, response rate was 100% with 2 mCR and 9 PR by Week 4 and survival was 88% at 2 months (7/8; 4 patients are alive and have not reached 2 months on study). Median survival has not been reached; median follow-up is 2.3 months (range 0.1-15.9 months). In terms of PD effects, monocyte and lymphocyte reduction generally occurred following the first priming dose and ferritin and CRP were reduced by an average of 40% and 50% by Day 6, respectively, for patients with windows of ELA026 treatment without concurrent chemotherapy effects. Study-wide (all patients dosed), treatment-related infusion reactions (~20%) and cytopenias (~30%) were generally manageable with supportive care and dosing modifications. One serious adverse event, a grade 4 infusion reaction, was assessed as related in a relapsed/refractory mHLH patient with acute liver failure and poor hemodynamic reserve. Infection risks are expected for this patient population, which were mitigated with growth factor support and antimicrobial prophylaxis. No deaths were related to study drug. Updated study results will be provided at the 2024 ASH meeting in San Diego. Conclusion: Data suggest ELA026 is well-tolerated to date in sHLH patients and results in a 100% response rate and improved 2-month survival in treatment-naïve mHLH patients. The study is enrolling in an expanded cohort to further assess efficacy in this patient population.

Background: Myeloproliferative neoplasms (MPNs) are chronic leukemias with increased thrombotic risk. Venous thrombosis in MPN often occurs in atypical sites, such as splanchnic vein thrombosis (SVT), defined by thrombosis in the portal, hepatic, mesenteric, or splenic veins. Data to guide anticoagulation management of SVT in MPN patients is lacking. Objectives: The purpose of this study is to evaluate outcomes as well as the safety and efficacy of different anticoagulation strategies in MPN patients with SVT. Methods: A retrospective cohort study of MPN patients with SVT from 10 international centers was conducted. All centers performed systematic identification of adults with a World Health Organization 2016 diagnosis of an MPN (polycythemia vera [PV], essential thrombocythemia [ET], myelofibrosis [MF], prefibrotic MF, MPN-unclassifiable [MPN-U]) and confirmed SVT. Inclusion criteria were met if first SVT occurred after or within one year before MPN was diagnosed. The primary outcome was 1-year cumulative incidence of recurrent venous (VT) or arterial thrombosis (AT). Secondary outcomes included 1-year cumulative incidence of (1) major and clinically relevant non-major bleeding (CRNMB) by International Society on Thrombosis and Hemostasis criteria, (2) SVT recanalization; and (3) 1-year overall survival. Death as a competing risk was used for cumulative incidence analyses of recurrence and bleeding. Results: 486 MPN patients (median age at first SVT 51 years; 62.3% female) were identified. MPN diagnosis preceded SVT in 35.2% of patients (median time 4.8 years) and occurred simultaneously or within 1 year of first SVT in 64.8% of patients. 43.8% of patients had PV, 23.7% ET, 14.2% MF, 3.1% prefibrotic MF and 13.2% MPN-U. The most common driver mutation was in JAK2 (90.7%) followed by CALR (4.4%) and MPL (1.6%). SVT localization was isolated to portal (25.7%), hepatic (15.4%), mesenteric (1.9%), and splenic veins (4.3%), and in 51.2% of cases SVT occurred in multiple vessels. Prior VT or AT occurred in 8.8% and 4.1% of subjects, respectively. Cytoreduction (most commonly hydroxyurea [36.9%], interferon [9.6%] or JAK inhibitor [6.8%]) was started after SVT in 58.7% of newly diagnosed MPN patients and 40.6% of those with known MPN. 57.6% of patients were anticoagulated, 3.5% of patients were treated with an antiplatelet agent, and 11.7% were treated with both. The most common initial anticoagulants were vitamin K antagonists (VKA) (29.2%), direct oral anticoagulants (DOAC; 20.4%), and low-molecular-weight heparin (LMWH; 10.5%). DOACs were more commonly used in the USA and Asia than Europe (21.2%, 52%, and 13.5%; p<0.001). The median duration of anticoagulation was 23.9 months, with 62.8% still on anticoagulation after 3 years or at last follow-up. 1-year cumulative incidence of recurrent VT and AT was 14% (95% CI 11-18) (5.8% for recurrent SVT [95% CI 3.9-8.3]; 6.3% for other VT [95% CI 4.3-8.8]; 2.4% for AT [95% CI 1.3-4.2]), with an overall time to event 89 (IQR 34-193) days. Thrombosis incidence was similar in patients initially treated with VKA (13%), DOAC (15%) or LMWH (16%) (p=0.93); in comparison, individuals not treated with anticoagulation had 1-year thrombosis incidence of 13% (p=0.22). 1-year major and CRNMB cumulative incidence in all patients was 5.8% (95% CI 3.9-8.2) and 8.5% (95% CI 6.1-11), with median time to event 68 (IQR 13-150) days. Incidence of major bleeding was similar in VKA, DOAC, and LMWH-treated patients (5.9%, 6.6%, and 4.0%; p=0.89). 1-year cumulative incidence of SVT (partial) recanalization was 13% (95% CI 9.8-16) in all patients, with a median time to recanalization of 127 (IQR 40-323) days; recanalization rates were similar in anticoagulated and non-anticoagulated patients (p=0.76). There was a trend toward higher recanalization rates in patients treated with DOAC (26.9%) than with VKA (21.5%) or LMWH (13.6%; p=0.28). 1-year overall survival was 94.2% (95% CI 91.8-96.1) and similar between treatment groups (VKA 96.7%, DOAC 95.6%, LMWH 89.7%; p=0.11) and for no anticoagulation (82.3%; p=0.32). Conclusions: This is the largest contemporary cohort of MPN patients with SVT. MPN patients with SVT remain at risk for short-term thrombosis and bleeding complications regardless of treatment. We found no significant differences in outcomes between anticoagulation strategies, including in patients treated with DOACs compared to VKA or LMWH.

Background: Zamto-cel is an investigational autologous tandem CD20-CD19-directed non-cryopreserved CAR-T cell product administered as a fresh formulation to patients (pts) with relapsed/refractory Diffuse Large B Cell Lymphoma (r/r DLBCL) in the DALY II USA clinical trial (NCT04792489), a multicenter, open label, single-arm Phase 2 study. Here, we report efficacy and safety outcomes as part of a pre-planned interim analysis of 59 evaluable patients and 69 patients in the safety population. Methods: Eligible adults had r/r DLBCL after at least 2 prior lines of treatment including anti-CD20 monoclonal antibody and anthracycline-containing regimen and measurable disease per Lugano 2014 classification. Zamto-cel was manufactured utilizing CliniMACS Prodigy® (Miltenyi Biotec), a closed, automated system with a 14-day vein-to-vein time and administered as a fresh formulation. Lymphodepletion chemotherapy was initiated during the manufacturing process (either cyclophosphamide/ fludarabine or bendamustine) prior to receiving a single dose of zamto-cel at a dose of 2.5x106 CAR T cells/kg on Day 0. The primary endpoint was overall response rate (ORR) defined as best overall response (BOR) of either complete response (CR) or partial response (PR). Secondary endpoints included complete response rate (CRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), safety, and CD19 and CD20 antigen expression at relapse. Results: As of March 29th, 2024, 69 pts received zamto-cel of which 59 were evaluable having received a fresh, conforming product and completed a minimum of 3 months follow-up. Median age was 63 years (range 25-85), 39 (66%) were male. Sixteen pts (27%) received 3 or more lines of prior treatment. The majority of pts (53%) had elevated LDH at study entry, and 49% had ≥ 2 extranodal lesions, indicative of a study population with advanced disease. No pts received any bridging therapy, in the week after apheresis and before lymphodepletion. Only 7 pts (12%) received bendamustine as lymphodepleting regimen. Successful manufacturing of a fresh, in specification product occurred in 91.3% out of 69 treated pts. Four patients received a cryopreserved formulation to permit time for comorbid condition management. The mean viability of the final product was 96.0% with 29.4 % transduction efficacy. No patient died or withdrew during the manufacturing process. The ORR in the evaluable patient population (n=59) as assessed by an Independent Radiology Committee (IRC) was 72.9% (95% CI, 59.7-83.6), with a CRR of 49.2% (95% CI,35.9-62.5). The 6 month and 12 month-PFS was 55% (95%CI, 41-67) and 42% (95%CI, 28-56), respectively; 12 month-OS was 72% (95%CI, 57-83). The median DOR was 11.4 months. All 69 treated pts were assessed for safety outcomes. Treatment-emergent adverse events (TEAEs) were mostly of grade 1-2, the majority of grade ≥ 3 were hematological. Thirty-two pts (46.4%) experienced cytokine release syndrome (CRS), all grade 1-2. Immune effector cell-associated neurotoxicity syndrome (ICANS) was reported in 12 pts (17.4%), grade 1-2 (9 pts; 13.1%); grade 3 (3 pts; 4.3%). One patient experienced immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS), which resolved after 2 days. Biopsies at progression were available in 24 pts. CD19-negative relapse (defined as H Score <100) was seen in 2 pts, CD20-negative relapse was observed in 3 pts. Only one patient experienced loss of both antigens compared to pre-treatment status, demonstrating that most lymphomas maintain target antigen expression at relapse after treatment with zamto-cel. Conclusion: This pre-planned interim analysis represents the first pivotal trial of a tandem CD20-CD19 directed non-cryopreserved CAR-T cell product for patients with third-line r/r DLBCL. The trial plans to enroll 100 evaluable patients and the final data will be presented upon study completion. Among the 59 evaluable patients at the interim analysis, there is encouraging activity and a favorable safety profile in DLBCL patients treated with zamto-cel. Unlike currently registered CAR-T cell products, zamto-cel is administered as a fresh product with a short vein-to-vein time of 14 days with lymphodepletion initiated during the manufacturing process. With a manufacturing success rate of 91% we have demonstrated the feasibility of this process among high-risk patients with r/r DLBCL.