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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.

Background: Teclistamab (Tec), a first-in-class BCMA bispecific T-cell antibody, received regulatory approval for the treatment of RRMM based on the MajesTEC-1 study [Moreau et al, NEJM, 2022] which demonstrated an overall response rate (ORR) of 63% and median progression free survival (PFS) of 11.3 months. However, less than 15% (N=24) of patients (pts) enrolled in MajestTEC-1 were ≥75 years, an age cohort that is often underrepresented in clinical trials and comprises approximately one third of MM pts at diagnosis [SEER 22 2017-2021]. In this multicenter retrospective study, we report the real-world safety and efficacy of a large cohort of elderly (≥75 years) RRMM pts treated with Tec. Methods: Pts with RRMM who received standard-of-care Tec across 13 U.S. academic institutions were included in the study. The follow-up data cutoff was 30 April 2024. Pts were divided by age into two groups: age <75 years (<75 group) and age ≥75 years (≥75 group). High-risk cytogenetic abnormalities (HRCA) were defined as the presence of del(17p), t(4;14), t(14;16) and/or gain or amplification of 1q21. Disease response and progression was evaluated using IMWG criteria. Time-to-event analyses were evaluated using the Kaplan-Meier method. Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) assessment was based on the American Society for Transplantation and Cellular Therapy consensus grading. Results: Among 385 pts, 83 (22%) were in the ≥75 group (median age 78, range 75-92) and 302 (78%) in the <75 group (median age 65, range 31-74). Compared to pts in the <75 group, those in the ≥75 group were more often white (78% vs. 63%, p=0.009). Both the ≥75 and <75 age groups had a median of 6 prior lines of therapy, a similar proportion with ECOG ≥2 at start of Tec (29% vs. 24%, respectively; p=0.37), and a high proportion of pts with triple-class-refractory disease (77% vs. 85%, p=0.06) and pts who would have been ineligible MajesTEC-1 (73% vs. 80%, p=0.20). In contrast, pts in the ≥75 group had a lower incidence of adverse MM risk factors compared to the <75 group, including HRCA (44.6% vs. 57.9%, p=0.03), ultra high-risk (≥2 HRCA) MM (12% vs. 24%, p=0.02), extramedullary disease (22% vs. 40%, p=0.02), hemoglobin <8 g/dL (10% vs. 21%, p=0.02) or albumin <3 g/dL (6% vs. 19%, p=0.04) at the time of starting Tec. Moreover, a lower proportion of pts in the ≥75 group had prior autologous stem cell transplantation (43% vs. 72%, p<0.0001) or prior BCMA-directed therapy (33% vs. 55%, p=0.0003). The median time from diagnosis to start of Tec was longer for pts in the ≥75 group (7.21 years vs. 5.81 years, p=0.02). There was no significant difference in rates of any-grade CRS (52% vs. 59%, p=0.27), CRS grade 2-4 (10% vs. 11%, p=0.74) or any-grade ICANS (19% vs. 13%, p=0.12) between the ≥75 and <75 age groups, respectively. Four pts in the entire cohort developed CRS grade 3-4, one of whom was in the ≥75 group. Ten pts developed grade 3 ICANS (none grade 4), three of whom were in the ≥75 group. There was no significant difference between the ≥75 group and <75 group in ORR (62% vs. 53%, p=0.17) and ≥very good partial response (VGPR) rate (53% vs. 44%, p=0.14). After a median follow-up period of 9.9 months (95% CI 9.6-10.6 months), the median PFS in the ≥75 group was 10.7 months (95% CI 6.6-NR) vs. 5.2 months (95% CI 6.6-NR) in the <75 group (p=0.005). At the time of data cut-off, the median overall survival (OS) for pts in the ≥75 group had not been reached (95% CI NR - NR) compared to 16.1 months (95% CI 14.0 - NR) in the <75 group (p=0.048). In multivariable analysis for the entire cohort, age ≥75 was not significantly associated with either PFS (HR 0.87, 95% CI 0.54-1.39; p=0.55) or OS (HR 0.60, 95% CI 0.30-1.19; p=0.15). Conclusions: This analysis of a large cohort of RRMM pts treated with Tec in the real-world setting demonstrates comparable efficacy and safety outcomes in elderly (aged ≥75 years) pts to those reported in the overall study population of MajesTEC-1. The adverse baseline disease characteristics and inferior efficacy in pts <75 years age compared to ≥75 years likely reflect patient selection and prescribing patterns in the early era of access to commercial BCMA bispecific therapy with Tec. In multivariable analysis there was no significant impact of age ≥75 on survival outcomes. OP, DD & LF: co-first authors. KKP, HCL & AGC: co-senior authors

Introduction. Ciltacabtagene autoleucel (cilta-cel) and idecabtagene vicleucel (ide-cel), two anti-B-cell maturation antigen (BCMA) CAR T therapies, have demonstrated remarkable responses and improved survival among patients with relapsed/refractory multiple myeloma (RRMM) in the clinical trials and standard of care (SOC) setting. Here, we compare safety, efficacy, and survival for patients treated with SOC ide-cel and cilta-cel. Methods. Data were from a retrospective chart review of RRMM patients leukapheresed by 12/31/2022 with the intent to receive SOC ide- or cilta-cel at 19 institutions in the US Multiple Myeloma Immunotherapy Consortium. An inverse probability of treatment weighting (IPTW) approach was used to compare outcomes by therapy type (cilta- vs. ide-cel), balancing on age, sex, race and ethnicity, performance status, extramedullary disease, high-risk cytogenetics, prior BCMA therapy, bone marrow plasma cells, penta-refractory status, lymphodepleting chemotherapy, baseline ferritin, low cell dose, and bridging therapy response. Logistic regression and Cox proportional hazard models were used to examine the association of treatment type with safety, efficacy, and survival accordingly, while adjusting for IPTW weights. We employed propensity score matching utilizing the same covariates to identify the association of treatment type with progression-free survival (PFS) within relevant patient sub-groups. Results. A total of 641 patients were leukapheresed by 12/31/2022 with ide-cel (n=386) and cilta-cel (n=255). 586 patients were infused (n=350 for ide-cel; n=236 for cilta-cel) with a median follow-up of 13.0 and 12.6 months, respectively. After IPTW, patient characteristics were well-balanced. Patients treated with cilta-cel were more likely to have grade ≥ 3 cytokine release syndrome (CRS) (OR=5.52, 95% CI=1.76-17.30, p=0.004), infections (OR=2.07, 95% CI=1.44-2.97, p<0.001), and delayed neurotoxicity (NT) (OR=20.97, 95% CI=4.75-92.42, p<0.001) compared to patients treated with ide-cel. In the cilta-cel cohort, 24 patients (10%) experienced delayed NT compared to 2 patients (1%) in the ide-cel cohort. Although not statistically significant, patients treated with cilta-cel were more likely to have any second primary malignancies (SPMs) (OR=1.87, 95% CI=0.94-3.71, p=0.08) and any SPMs excluding non-melanoma skin cancers (OR=1.78, 95% CI=0.78-4.10, p=0.2) but no association was observed for odds of hematologic SPMs (OR=0.98, 95% CI=0.26-3.61). No association was observed for therapy type with any or severe immune effector cell-associated neurotoxicity syndrome, any CRS, severe cytopenias, and non-relapse mortality. Compared to ide-cel, cilta-cel was associated with better treatment responses of ≥ complete response (OR=2.38, 95% CI=1.61-3.51, p<0.001) and ≥ partial response (OR=1.74, 95% CI=0.99-3.05, p=0.06). Patients treated with cilta-cel had a longer PFS and overall survival (OS) than ide-cel (HR=0.47, 95% CI=0.35-0.62, p<0.001 and HR=0.63, 95% CI=0.42-0.93, p=0.02, respectively), and these findings were similar in the intention to treat cohort (PFS: HR=0.44, 95% CI=0.34-0.55, p<0.001; OS: HR=0.55, 95% CI=0.41-0.73, p<0.001, respectively). We observed consistent findings when repeating the analyses restricting the ide-cel cohort to patients infused during the same time-period as FDA approval for cilta-cel (≥ March 2022), restricting to patients with data on all covariates, and restricting to sites that contributed data for both products. In a propensity matched population, (n=380; n=190 for cilta-cel and n=190 for ide-cel), patients treated with cilta-cel had superior PFS compared to those treated with ide-cel in most subgroups with respect to age and disease characteristics including extramedullary disease, high-risk cytogenetics, and elevated baseline ferritin (p<0.05). Conclusion. Our results suggest superior efficacy of cilta-cel with a higher incidence of certain toxicities compared to ide-cel in the SOC setting. This study provides valuable information for patient counseling and guiding the selection of CAR T-cell therapy for specific patient populations. Further validation through similar large-scale real-world experiences or prospective studies is needed to confirm our results and enhance applicability in the clinical setting. *DH, LP, & DD are co-first authors * YL, KP, & SS are co-last authors

Introduction TP53 alterations (TP53+) are seen in <5% of patients (pts) with chronic myeloproliferative neoplasms (MPNs) but are more common in accelerated/blast phase (MPN-AP/BP) [Luque Paz D, et al 2020]. While pts with low-burden TP53+ (Variant allele frequency (VAF) <5%) may remain stable for years [Kubesova et al, 2018]; biallelic loss of TP53 is thought to confer higher risk for progression [Li et al, 2022] and worse overall survival (OS) than non-TP53+ pts [Rolles et al, 2023]. However, TP53 abnormalities have not been incorporated into currently utilized molecular based prediction models (MIPSS or MIPSS70) or compared with currently validated high molecular-risk (HMR) mutations (mut). We report the outcomes of the largest cohort of TP53+ MPN pts to date in comparison with HMR mut, and identify a VAF cut-off associated with highest risk of progression to MPN-AP/BP. Methods We retrospectively reviewed 2583 MPN pts from Mount Sinai Hospital (MSH) and Memorial Sloan Kettering Cancer Center (MSK) with at least one next generation sequencing (NGS) performed. Deidentified data from an additional cohort of 8 TP53+ MPN pts was received from University of Miami Sylvester Cancer Center (UMiami). Patient characteristics such as MPN subtype, gender, age at MPN diagnosis, driver mutation, thrombosis history were recorded. We also recorded date of transformation to MPN-AP/BP, dates of NGS testing, mutational and cytogenetic data, and survival status. We defined multi-hit TP53 as presence of =/>2 TP53mut, VAF > 50% or TP53 mutation + 17p deletion. Additional cohorts of pts with HMR mut (ASXL1, EZH2, IDH1/2, U2AF1, SRSF2 as per MIPSS70v.2) from MSH and non-TP53+ pts from the MPN-Research Consortium Tissue Bank were used as comparator arms. Patient characteristics were compared between TP53 single-hit and multi-hit using Chi-Sq test for categorical variables and Kruskal-Wallis test for continuous variables. Cumulative incidence function and Kaplan-Meier method were used to compare leukemic transformation and OS, respectively, between groups. Successive VAF levels with minimum groups of 25% of the total cohort were used to identify an optimal VAF cut-off. Results Of the 2583 MPN pts from MSH and MSK, 66 pts (2.6%) were found to have a TP53 mutation. Including 8 additional pts from UMiami, we analyzed a total of 74 TP53+ MPN pts; 40 single-hit and 34 multi-hit. Median age at MPN diagnosis was 61 years with a male predominance (60%). Distribution of driver mut was similar in single-hit vs multi-hit cohort with JAK2V617F being the most common (58%), whereas 11% of pts had triple negative disease . Thrombotic history was available for 45 TP53+ pts, with a high frequency of venous/arterial thrombosis (21/45 or 46.7%) in the TP53+ group as compared to 18.5% in the non-TP53+ MPN cohort (p= 0.0001). A significantly higher number of multi-hit TP53+ pts had a concurrent complex karyotype (79% vs 24% in single-hit; p<.001). MPN diagnosis at the time of detection of TP53+ was ET/PV (25.7%), MF (44.6%), MDS/MPN overlap syndrome (6.8%), MPN-U (2.7%) and MPN-AP/BP (20.3%), respectively. One or more genetic samples with TP53+ was available prior to transformation to MPN-AP/BP in 77% of pts (21/34 multi-hit; 36/40 single-hit) while a TP53+ was detected at the time of MPN-AP/BP diagnosis in the rest. Multi-hit TP53+ was associated with a significantly higher incidence of transformation to MPN-AP/BP as compared to single-hit; [65% vs 17.5%; HR=4.08 (1.71-9.71), p=0.0015]. Compared with HMR mut, multi-hit (HR=2.41; p=0.004) but not single-hit (HR=0.53; p=.277) TP53+ MPN pts were found to have a significantly increased risk of MPN-AP/BP transformation. One-year OS from the time of mutation detection was significantly inferior for both multi-hit (53.3%) and single-hit (75%) TP53+ pts as compared to HMR mut (98.8%, p=<.001). Cut-point analysis identified VAF >36% to be associated with the highest risk of transformation (HR=3.08) with lowest p-value (0.002). Conclusions Multi-hit TP53 alterations are associated with a significantly increased risk of leukemic evolution as compared to previously validated HMR mut, whereas both multi and single-hit TP53 mut are associated with worse OS highlighting the importance of TP53 in MPN disease progression.

Background: Tec is a BCMA-directed bispecific antibody (BsAb) approved for RRMM after ≥4 prior lines of therapy (LOT) based on the MajesTEC-1 trial. However, patients who had previously received a BCMA-DT were excluded from MajesTEC-1. Herein, we evaluated outcomes of RRMM patients with prior exposure to BCMA-DT treated with standard-of-care Tec. Methods: This was a multicenter retrospective cohort study. We compared variables between different groups using Chi-squared and Kruskal-Wallis tests, and assessed progression free survival (PFS) and overall survival (OS) using Kaplan Meier and Cox proportional hazards model. We used the maximally selected rank statistics method to determine the optimal cut-off point for continuous variables to find the most significant difference in PFS among different groups. Results: A total of 385 patients were included in this study. 193 patients had received a prior BCMA-DT, of whom 77%, 22%, and 1% had received 1, 2, and 3 prior anti-BCMA agents, respectively. In patients who had received a prior BCMA-DT, 35% were aged ≥70 years, 24% had ECOG performance status (PS) ≥2, 61% had high-risk FISH, 32% had extramedullary disease (EMD) at Tec initiation, and 42% were penta-refractory. Compared to the cohort without prior BCMA-DT (n=192), patients who were treated with prior BCMA-DT were more likely to have high risk FISH (61% vs 49%, p=0.02), and higher median number of prior LOT (7 vs 5, p <0.001). The specific types of prior BCMA-DTs with the respective overall response rate (ORR) to the most recent prior BCMA-DT were: antibody drug conjugate only (ADC, n=47, ORR 43%), chimeric antigen receptor T-cell therapy only (CAR T, n=99, ORR 86%), BsAb only (n=6, ORR 100%), ADC + CAR T (n=36, ORR 56%), and other ADC/CAR T/BsAb combinations (n=5, ORR 60%). Median follow up was 9.9 (95% CI:9.5-10.6) months. Patients with prior receipt of BCMA-DT had a lower ORR (51.4% vs 61.5%; p=0.012) and ≥very good partial response rate (39.4% vs 52.6%, p=0.009), but similar ≥complete response rate (22.3% vs 24%; p=0.78) to Tec compared to those without prior BCMA-DT. Moreover, patients with prior BCMA-DT had worse median PFS compared to patients without prior BCMA-DT (prior BCMA-DT: 4.6 months, 95% CI: 2.7-7.5; without prior BCMA-DT: 8.2 months, 95% CI: 5.7-12.2; p=0.017). On multivariable analysis incorporating prior BCMA-DT, age, cytogenetics, EMD, and ECOG PS, receipt of prior BCMA-DT was not independently associated with PFS (HR 1.25, 95% CI 0.95-1.64, p=0.1). The estimated 1-year OS rate was 58.9% (95% CI: 51.64-67.2) for the prior BCMA-DT group vs 65.1% (95% CI: 58.1-73.1) for the group without prior BCMA-DT, p=0.16. For the prior BCMA-DT cohort, response rates to Tec were numerically higher in patients who received CAR T (ORR 51.2%) followed by ADC (ORR 45.5%), and bispecific (ORR 30%) as their most recent prior BCMA-DT (p=0.39). No significant difference in PFS was noted when stratifying patients by number of prior BCMA-DTs, types of all prior BCMA-DTs received, type of most recent prior BCMA-DT, or depth of response to most recent BCMA-DT. Patients who responded to Tec had a numerically longer median time from most recent BCMA-DT exposure to Tec initiation compared to non-responders: 10.5 vs 7.5 months, p=0.48. We found that the optimal cut-off for time from last BCMA-DT exposure to Tec initiation was 8.7 months. Patients with > 8.7 months between last exposure to prior BCMA-DT and Tec initiation had a superior median PFS with Tec (8.1 months, 95% CI: 4.6-11.7) compared to patients with < 8.7 months from last exposure to prior BCMA-DT (2.5 months, 95% CI: 1.1-5.7), p=0.001. The toxicity profile for patients with prior BCMA-DT was similar to those who had not received a prior BCMA-DT. Grade ≥2 CRS occurred in 8.7% vs 13% (p=0.18), and grade ≥2 ICANS in 7.7% vs 6.7%, (p=0.85) of patients with and without prior BCMA-DT, respectively. Patients in the prior BCMA-DT cohort were more likely to have grade 3 thrombocytopenia in the first 30 days after Tec initiation (10.7% vs 6.6%; p=0.08). Conclusion: This is the largest study to date of any BCMA-directed BsAb among BCMA-exposed patients. Receipt of prior BCMA-DT was associated with a trend toward worse PFS, although not statistically significant, and lower likelihood of attaining an overall response. Waiting >9 months between sequencing BCMA therapies may be associated with improved PFS. D.D., M.A.V.M., J.A.D: co first authors; F.A., C.F., L.S.: co senior authors

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.

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.

Introduction: The BMT CTN 1704 study developed and validated the CHARM that stratified risk for non-relapse mortality and overall mortality among older adults, performing better than the HCT-CI alone (Artz A et al, Blood. 2023;142:109) and equally to two machine learning models. CHARM assigns a total score for 7 health variables: increasing age, higher HCT-CI scores, lower albumin, higher C-reactive protein, higher percent of weight loss over the preceding year, lower patient-reported performance status scores, and lower cognitive score per Montreal cognitive assessment (MoCA). A CHARM calculator is available at:https://cibmtr.org/CIBMTR/OffNav/DevSandbox/CHARM-Risk-NRM-Calculator No multi-institutional prospective data exist on functional trajectories and morbidity after HCT in older patients. We now report on the association of CHARM to trajectories of secondary morbidity outcomes among allo-HCT survivors of this large, prospective study. Patients and Methods: Allo-HCT candidates, aged ≥60 years (yrs), were enrolled (n=1226) from 49 centers in the US between 2019 - 2021. The primary analysis includes 1105 patients proceeding to allo-HCT on study and secondary endpoints were assessed at day (D) 100, 180 and 365 except MoCA and organ toxicity were restricted to D100 and frailty had inadequate data for D100. A sequential multiple imputation strategy was implemented to impute endpoints for survivors at each time point with missing data. Analyses on multiply imputed datasets were conducted and the results combined using Rubin's rule. Associations between CHARM scores and secondary outcomes were analyzed using a multivariable Cox, Fine-Gray, Generalized Estimating Equations, and logistic regression model for survival, competing risks, continuous, and binary outcomes, respectively, with latter two focused on surviving patients. Models were adjusted for other variables including conditioning intensity, graft-versus-host disease (GVHD) prophylaxis regimen, disease-risk index, donor-recipient gender match, ethnicity, baseline value of the dependent variable, and visit timepoints. Results: Higher CHARM scores were associated with development of serious organ toxicities by D100 (OR: 2.05, [1.52-2.78], p<0.0001) and ≥2 worsening score on the MoCA (odds ratio (OR) 1.55 [1.16-2.1], p=0.003). Among survivors at all timepoints, higher CHARM scores were associated with greater disability by instrumental activities of daily living (IADL) (Slope -0.640 [-0.433-0.846], p<0.001) and worsening Patient-Reported Outcomes Measurement Reporting System (PROMIS) physical function (Slope -0.981 [-0.057 - -1.904], p=0.037), depression (Slope 0.763 [0.042-1.484], p=0.038) and in a lesser magnitude anxiety (Slope 0.659, p=0.076). Among survivors at D180 and D365, higher CHARM scores were associated with worse frailty (Slope 0.193 [0.081-0.305], p<0.001). CHARM scores were not associated with development of acute GVHD grades 2-4 or 3-4 but were associated with post-GVHD increased mortality (HR: 1.61, [1.25-2.08], p=0.0002). Higher CHARM scores are associated with a lower incidence of chronic GVHD (HR: 0.83, p=0.026), likely due to the effect of CHARM on the competing risk of death leaving fewer patients at risk for chronic GVHD. Conclusions: The novel primary CHARM, originally developed to predict risks of NRM, also predicts worse frailty, disability, cognitive decline, and serious organ toxicities; outcomes that are critically important to older recipients of allo-HCT. CHARM therefore informs risks of transplant morbidity, separate from risks of developing acute GVHD. Results further support adopting CHARM in practice to counsel patients, expedite HCT referrals for lower risk CHARM, and design trials for high CHARM score patients.

Background: The majority of patients respond to steroid treatment for graft-vs-host disease (GVHD), but the typically high doses and prolonged courses can cause substantial morbidity. GVHD can be classified at onset into two groups with significant differences in treatment response and non-relapse mortality (NRM) by clinical criteria (Minnesota risk) but the more favorable standard risk group still experiences high rates of treatment failure and NRM [MacMillan, BBMT 2015]. We previously validated a serum biomarker-based (ST2+REG3α) risk stratification system, MAGIC algorithm probabilities (MAPs), that can stratify patients both at initiation and during treatment into risk groups for treatment response and NRM [Hartwell, JCI Insight 2017, Srinagesh, Blood Adv 2019]. GVHD that is Minnesota standard risk and has a low MAP (i.e., Ann Arbor 1) at start of treatment represents a low risk group with >80% response rate to steroids and ~10% NRM [Etra, Blood 2023]. We hypothesized that serial monitoring of GVHD symptom severity and MAPs twice (days (d) 7 and 14) in patients with clinical and biomarker defined low risk GVHD could further stratify patients into clinically meaningful groups. Methods: We retrospectively determined MAPs at d7 and 14 in 450 patients with low risk GVHD who participated in a prospective, multi-center, observational trial and were treated with systemic steroids between 2015-2023. MAPs <0.291 at days 7 and 14 were defined as low risk based on a previously validated threshold [Major-Monfried Blood 2018]. Clinical responses were scored as complete (CR), partial (PR), or non-response (NR) by standard criteria. Initiation of second line therapy was considered NR. Patients were categorized into three groups (A-C) based on clinical responses and MAPs at days d7 and 14. A: CR/PR by d14 and low MAP at both d7+14; B: stable or worse GVHD (NR) by d14 with low MAP at both d7 and 14; C: any response with a high MAP at d7 or 14. The endpoints were clinical response at day 28 (overall response rate, ORR=CR or PR), regardless of earlier response status, and 6-month NRM. Results: The median age of the study population was 54 years (range: 0-79); 19% of patients received PT-Cy for GVHD prophylaxis. Target organ involvement was skin ± upper GI (66%), lower GI (23%), isolated UGI (11%), and skin+liver (1%), and GVHD severity was grade I (35%), II (61%), and III (4%) at start of treatment. Patients in group A (n=310, 69%), clinical responders with low MAPs through day 14, had excellent d28 ORR (93%) and very low NRM (4%). GVHD in this group was considered ultra-low risk (ULR) and subset analyses revealed highly consistent d28 ORR and NRM, regardless of target organ severity, age (<18, 18-59, >60), HCT-CI score, conditioning intensity, and GVHD prophylaxis. Group B patients comprised clinical non-responders with low MAPs through day 14 (n=112, 25%); half of them responded by d28 and their NRM was low (8%), albeit double that of group A (p=0.079). Group C was small (n=28, 6%) and included both clinical responders (n=20, 4%) and clinical non-responders (n=8, 2%) who had at least one high MAP through day 14. Their d28 ORR was 54% but NRM increased four-fold (32%) and was significantly worse than patients who maintained low MAPs regardless of clinical response (p<0.001). Conclusion: Serial monitoring by clinical response and biomarkers during the first two weeks of treatment identifies a small number of high risk patients whose GVHD is initially low risk (group C). This group experiences high NRM regardless of clinical response to steroid treatment and may benefit from treatment escalation. Patients with low risk GVHD who do not have an early clinical response to steroids but maintain low MAPs, (group B) have reasonably good long-term outcomes with standard treatment. Finally, serial monitoring identifies a very large subset of patients with ULR GVHD (group A) who respond exceptionally well to standard treatment and experience very low rates of 6-month NRM regardless of pre-transplant characteristics and GVHD prophylaxis. Such patients may benefit from treatment de-escalation strategies such as shorter courses of lower dose steroids, a strategy we are currently testing in a clinical trial (NCT05090384).

Background Endpoints for GVHD treatment trials use early response (i.e, day (D)28 of treatment) as a surrogate for long term survival. Overall response (OR) that combines complete (CR) and partial responses (PR) at day (D) 28 is the conventional endpoint for primary acute GVHD trials because of similar survival outcomes between CR and PR. D28 OR ignores symptom severity at baseline and D28, however, and the PR category encompasses a wide range of responses from minimal improvement to near complete resolution of symptoms. D28 OR is the only endpoint currently approved by the FDA for efficacy, but it has not been re-evaluated as an endpoint for primary treatment (1L) in fifteen years and little is known regarding the prognostic value of D28 OR as an endpoint for second line treatment (2L) of GVHD. We hypothesized that refinement of the current D28 OR criteria, particularly through recategorization of PR in the GI tract, the main driver of nonrelapse mortality (NRM), would more accurately reflect disease control and better predict survival outcomes than current D28 response. Methods The Japanese Society for Transplantation and Cellular Therapy (JSTCT) collaborated with the Mount Sinai Acute GVHD International Consortium (MAGIC) to develop and validate D28 refined response (RR) criteria for 1L and 2L treatment (tx) in patients with Grades II-IV acute GVHD. To maximize the correlation between treatment success (i.e, response) with long term survival, our primary measured metric was the negative predictive value (NPV). We first randomly divided the 1L tx cohort of JSTCT into the training (n=2341) and validation sets (n=1156). In the training set we used a classification and regression tree (CART) algorithm to generate RR criteria that predicted 6-month (mo) NRM based on symptoms both at tx onset and D28. We then compared the two D28 response endpoints (RR vs OR) as surrogates for 6-mo NRM in two validation sets of both 1L tx (JSTCT: n=1156; MAGIC: n=1141) and 2L tx (JSTCT: n=510; MAGIC: n=196). Results The CART algorithm defined a RR as GVHD Grades 0/I at D28 without additional tx; all other D28 grades were considered refined nonresponses. As expected, RR successfully stratified the risk of 6-mo NRM in both 1L tx validation sets (JSTCT: 8% vs 38%, p<0.01; MAGIC: 9% vs 37%, p<0.01). We defined a discordant nonresponse as a nonresponse by RR criteria but a response by OR criteria, which accounted for the majority (~75%) of differences between RR and OR. 6-mo NRM in discordant nonresponders was four fold higher than in responders (JSTCT: 35%; MAGIC: 30%). The large majority (>80%) of discordant nonresponders had persistent GI GVHD at D28. Because the proportion of discordant nonresponders was small (<7% of the total population) in the 1L setting, the improvements of an already high NPV were small (JSTCT: 93% vs 91%; MAGIC: 91% vs 90%). In the 2L tx validation sets, RR also stratified the risk of 6-mo NRM (JSTCT: 26% vs 56%, p<0.01; MAGIC: 13% vs 55%, p<0.01). At the time of 2L tx, the discordant nonresponders are more common and half of the discordant nonresponders experienced 6-mo NRM (JSTCT: 45%; MAGIC: 59%); as a result, RR achieved much higher NPVs than OR (JSTCT: 75% vs 66%; MAGIC: 87% vs 76%). Deaths in responders from acute GVHD (vs. other causes such as infection) were more frequent in OR than RR in both 2L tx validation sets (JSTCT: 41% vs 20%; MAGIC: 41% vs 13%) and 1L tx validation sets (JSTCT: 25% vs 18%; MAGIC: 32% vs 29%). D28 RR is superior to OR because it more accurately reflects control of serious GVHD in four independent validation cohorts, particularly in patients with GI disease. Conclusion We conclude that RR is a more accurate endpoint than OR in patients with grade II-IV GVHD primarily because it classifies persistent GI GVHD at D28 as a non-response instead of a response, which correlates with 6-mo NRM and achieves a higher NPV. This validated RR metric can serve as a better endpoint than OR in assessing treatment efficacy in both primary treatment trials that enrich for high risk GVHD, e.g. GI involvement, and second line treatment trials.