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Abstract Background: Population registries and the Alliance co-operative group database have highlighted racial disparities in AML survival attributed to differential prevalence and impact of oncogenic drivers on disease biology. However, the small number of Black patients with well-annotated genomic profiles limits the validity of these findings. The current study leverages ECOG-ACRIN cytogenetic and outcomes data from newly diagnosed adult AML patients treated on intensive chemotherapy-based clinical trials over three decades. Methods: Self-reported race was categorized as White, Black or Other. Descriptive statistics were used to summarize baseline characteristics using the Wilcoxon rank-sum and Fisher's exact tests. Multivariable Cox proportional hazards regression models evaluated the association between race and survival outcomes adjusting for age, hemoglobin, platelet count, white blood cell count, blast percentage, performance status and ELN cytogenetic risk score (RS). All Cox models were stratified by protocol. Subgroup analyses of overall survival (OS) and disease-free survival (DFS) were performed using Kaplan-Meier curves stratified by race using log-rank tests. All statistical tests were two-sided. Analyses included only patients with complete data for the variables of interest. Results: Data was collected across 10 phase II and III interventional trials for newly diagnosed adult AML that accrued patients between 1984 and 2019. The study population included 3469 White, 184 Black, and 156 Other patients with a Black representation of 1.1-11% across trials. Blacks were significantly younger at diagnosis with a median age of 47.9 years compared to 53.5 years in Whites (p<0.001). Racial groups were well matched for gender and performance status. Black race was an independent prognostic factor for inferior OS (HR 1.212, CI 1.01 – 1.453; p = 0.0383) and DFS (HR 1.313, CI 1.05-1.641; p = 0.017). Complete cytogenetic results were available for 117 Black and 2162 White patients and revealed no significant racial differences in the distribution of ELN 2017 cytogenetic RS, although core binding factor AML was non-significantly enriched in Black patients (12.8% vs 8.3%). No difference was observed between Blacks and Whites in the prevalence of complex karyotype (CK), CK with -5/del(5q), -7/del(7q), or -17/del(17p), and AML-MRC including +8 and del(20q). Notably, the ELN 2017 cytogenetic RS effectively predicted OS in Black (57.8 vs 14.2 vs 5.8 months in favorable, intermediate and adverse RS, p = 0.018), and White patients (60.1 vs 15.2 vs 7.1 months, p < 0.0004 for Whites) but only predicted DFS for White AML patients (p < 0.0001 for Whites, p=0.48 for Blacks). In patients with molecular data for FLT3-ITD (n=1218), CEBPA (n=576), TP53 (n=572), or NPM1(n=683), no racial difference in the prevalence of these mutations was observed. However, NPM1 mutations were associated with inferior OS in Blacks compared to Whites (19.1 vs 8.9 months; p = 0.0095). Black and White AML patients had similar responses with complete remission rates of 58.2% vs 57.5%, p=0.55, and treatment tolerability with 30-day mortality of 7.1% vs 8.9%, p=0.50. However, consolidation approaches differed significantly. Among patients that underwent stem cell transplant (SCT), a significantly higher percentage of White patients received allogenic SCT compared to Blacks (48.5% versus 37.1%, p <0.01). Conclusions: This study represents one of the largest race-based comparisons of cytogenetic abnormalities and clinical outcomes in prospective trials of intensive chemotherapy in AML . Our data confirms the independent prognostic relevance of race in AML survival and validates the predictive ability of the ELN 2017 cytogenetic RS for OS across racial groups. There is ancestry-based attenuation of the survival benefit of NPM1 mutations as previously reported, underscoring the need to tailor the current treatment approach to NPM1 mutated AML based on race. The availability of NGS data limited the genomic analysis to a subset of patients. Future studies should examine the depth of treatment response incorporating MRD biomarkers and explore the effect of race on co-occurring mutations and the leukemic stem cell transcriptome to better explain the observed disparities. Finally, persistent disparities in access to allo-SCT even within the context of clinical trials reinforces the need to address diversity in the stem cell donor pool and social barriers to transplant.

Abstract Introduction Venetoclax combined with hypomethylating agents (VEN/HMA) is an approved frontline induction therapy for older or unfit patients with acute myeloid leukemia (AML). However, data comparing its efficacy and safety to intensive chemotherapy (IC) in intermediate-risk AML—characterized by molecular and cytogenetic heterogeneity—remain limited. Methods This multicenter, real-world retrospective study analyzed newly diagnosed intermediate-risk AML patients who received either VEN/HMA or IC. We evaluated composite complete remission (CRc) rates, transfusion and infection rates, long-term outcomes including overall survival (OS) and progression-free survival (PFS), and performed subgroup analyses to identify mutation-specific predictors of treatment response. Multivariable Cox regression was used to identify independent prognostic factors. Results A total of 229 intermediate-risk AML patients were included. VEN/HMA achieved a comparable CRc rate to IC (75.3% vs. 63.4%) with lower transfusion needs and fewer infections. Patients harboring FLT3-ITD, DNMT3A, or TET2 mutations showed greater benefit from VEN/HMA, while KIT-mutated patients responded more favorably to IC. Among patients who did not undergo allo-HSCT, VEN/HMA significantly improved 3-year OS (P = 0.001) and PFS (P = 0.008). No significant OS or PFS difference was observed in the allo-HSCT subgroup. In MRD-negative patients without transplant, those treated with VEN/HMA had superior OS compared to IC. Multivariable analysis identified VEN/HMA (HR = 0.613, P = 0.038) and allo-HSCT (HR = 0.11, P = 0.001) as independent predictors of better survival. Conclusions VEN/HMA is a safe and effective induction strategy for intermediate-risk AML, particularly in patients with BCL-2 inhibitor–sensitive mutations (FLT3-ITD, DNMT3A, TET2). These findings support a genotype-guided treatment approach in AML, complementing current risk stratification frameworks and informing individualized induction therapy decisions.

Abstract Background: The Multiple Myeloma Research Foundation (MMRF) and its partners launched the MyDRUG platform clinical trial (NCT03732703) to evaluate the safety and efficacy of genomically-guided treatments for functional high-risk relapsed/refractory myeloma patients (fHRMM). fHRMM patients with no discernible activating mutations and who had received 1-3 prior therapies (exposed to at least one proteasome inhibitor and an IMiD) were given a combination of daratumumab (D), ixazomib (I), pomalidomide (P) and dexamethasone (d) (D-IPd) quadruplet therapy. The goal of this study is to evaluate the immunomodulatory effects of daratumumab-(anti-CD38)-based therapy on fHRMM patients enrolled in the MMRF-sponsored MyDRUG umbrella clinical trial over the duration of therapy and to correlate immune changes with patient response immediately following the first two cycles of therapy. Methods Bone marrow (BM) aspirates were collected at baseline (BL) prior to therapy, at the end of 2 cycles (EOC2), 4 cycles (EOC4) of the quadruplet therapy and at the end of treatment (EOT) or progressive disease (PD). CD138-negative bone marrow mononuclear cells were isolated for profiling the immune microenvironment using scRNAseq, scTCRseq and CyTOF. Results Single-cell RNA and TCR profiles were generated from ~90,000 cells across 41 samples from 16 subjects. scRNAseq identified CD3+ T cells, NK cells, classical and non-classical monocytes and B cells. CD8+ T cells were further resolved into their subsets including precursor (TPEX) and terminally exhausted T cells (TEX) within the bone marrow microenvironment. Within the CD8+ T cell compartment, an expansion of the effector memory (TEM) cell population was observed following 2-cycles of therapy (EOC2). However, this TEM expansion was not sustained at timepoint EOC4. Towards the end of therapy, enrichment of precursors to putative exhausted and terminal dysfunctional effector memory cells (TEMRA) was observed. Subjects with partial (PR), very good partial (VGPR) and complete (CR) best overall responses showed an initial increase in TEM cells followed by a slow expansion of TEX and TEMRAcells over time. One patient with progressive disease (PD) maintained the highest LAG3 expression across the cohort among CD8 T cell subsets (TEMRA, EM) and CD4 Tregs at baseline while observing a significant upregulation of PDCD1 in CD4 Tregs and CD8 Naive cells by EOC2. Cell-cell communication network analysis identified secreted ligands between responders (CR/VGPR) and partial responders (PR) at EOC2. Samples with PR exhibited upregulation of signaling of TNF from the CD8 Naïve compartment (p=0.048, Wilcoxon), IFNG from the CD8 EM (p=0.073, Wilcoxon) and TEMRA (p=0.048, Wilcoxon) populations along with IFNG (p=0.073, Wilcoxon) from NK cells. CD14+ and CD14+16+ Monocytes on the other hand showed enrichment of LGALS9 (p=0.03 (CD14+), p=0.048 (CD14+CD16), Wilcoxon) in the PR group at EOC2 relative to responders. Finally, longitudinal tracking of T cell clonality showed preferential progressive expansion of TEMRA cells after the therapy. We mapped hyperexpanded (more than 16 copies) clonotypes, presumed to be tumor-reactive, to various CD8+ T cell subsets. These hyperexpanded clonotypes are mapped to the TEMRA, TEX and TEM CD8+ T cells. Analysis of TCR repertoires clonality and diversity also demonstrated a reduced richness and increased clonality of CD8+ TCRs in responders. Summary/Conclusion These preliminary analyses of D-IPd quadruplet therapy of RRMM indicate that paired single cell RNA and TCR sequencing of BM T cells suggests a selective expansion of clonotypic CD8+ T cells. When considering patient response, the only PD patient profiled in this study maintained an exhaustive signature (LAG3, PDCD1) in multiple T cell compartments at BL. The differential expression of the receptor ligand pairs after treatment between different clinical response groups suggests an altered TME response that may inform future therapeutic stratification. These results support further explorations of rational combinations of targeted and immune therapies for greater efficacy in this disease.

Abstract Introduction Elevated levels of fetal hemoglobin (HbF) ameliorate sickle cell disease (SCD) manifestations. BEAM-101 is an investigational cell therapy comprising ex vivo base-edited autologous CD34+ hematopoietic stem and progenitor cells (HSPCs) that directly target the HBG1/2 promoters to disrupt BCL11A binding, switching production from sickle (HbS) to majority anti-sickling HbF. We present ongoing data from the BEACON study (NCT05456880), a Phase 1/2, single-arm, open-label study evaluating a single dose of BEAM-101 in individuals with SCD and severe vaso-occlusive crises (sVOCs). Methods Eligible patients were aged 12–35 years with SCD and ≥4 sVOCs in the 2-year period prior to informed consent. After mobilization with weight-based or tiered fixed-dose plerixafor, autologous CD34+ HSPCs were collected by leukapheresis and genetically modified with an adenine base editor. Following conditioning with pharmacokinetically adjusted myeloablative busulfan (target cumulative AUC 80 hr*mg/L), patients received a single dose of BEAM-101 (≥3.0×106 viable CD34+ cells/kg). Patients were then monitored for neutrophil and platelet engraftment, adverse events (AEs), total Hb, Hb fractions, % F-cells, hemolysis markers, sVOCs, and additional protocol endpoints for up to 24 months. Results As of June 16, 2025, enrollment has been completed and 46 patients have initiated mobilization. Of the 26 patients who have received BEAM-101, mean duration of follow-up was 6.2 (range 1.0–18.7) months. Baseline demographics were: age 18–34 years, 24 βS/βS genotype, 21 self-reported Black/African American, and 11 female. One patient, who successfully engrafted and obtained stable HbF levels >60%, withdrew consent 5 months post-infusion. For the 26 treated patients, the median number of stem cell collection cycles was 1 (range 1–4); 18 (69.2%) required a single cycle, 4 required 2 cycles, and 4 required >2 cycles. Target cell dose was achieved with a median of 3 (1–12) collection days. Patients received a mean BEAM-101 dose of 8.4 (range 3.2–23.4) ×106 viable CD34+ cells/kg. By the data cut, patients achieved neutrophil (n=26) and platelet (n=24) engraftment at a median of 18 (12–30) days and 19 (11–50) days, respectively, with a median duration of 7 (4–17) days of neutropenia. Of the 24 evaluable patients, 9 (37.5%) achieved platelet engraftment without requiring platelet transfusion through the transplant process. No patients had ≥Grade 3 AEs or serious AEs related to BEAM-101. One patient died due to respiratory failure, assessed as likely related to busulfan conditioning, 4 months post-infusion as previously reported. Mean total Hb increased to 12.1 (range 9.0–14.7) g/dL by Month (M) 1 (n=24), 15.6 (11.9–18.6) g/dL by M6 (n=11), and was sustained through follow-up. Four patients had total Hb levels above the normal range beyond M6 without any associated clinical manifestations or need for therapeutic intervention. Erythropoietin levels trended towards normal in all patients, including those with elevated total Hb. Mean endogenous HbF (HbF/[HbF+HbS]) was >60% and HbS was <40% by M1, which was sustained through last follow-up. At M6, mean % F-cells were 99.2% (97.0–99.9; n=10) and mean HbF/F-cell was 20.8 (18.0–23.9; n=9) pg, exceeding the protective threshold of 10 pg against sickling. Peripheral blood editing was at a mean of 68.5% by M3 (n=16), 69.6% by M6 (n=10), and 72.8% by M12 (n=5). Hemolysis markers and sickling parameters normalized or improved for all patients. No patients experienced any investigator-reported sVOCs post-engraftment. Conclusions The BEAM-101 treatment process is characterized by a low number of mobilization and collection cycles and high editing efficiency, resulting in rapid neutrophil and platelet engraftment and robust pancellular HbF expression, with durability observed up to 18 months. Additionally, there is a corresponding reduction in HbS levels to <40%, and improvements or resolution of hemolysis parameters and anemia, along with resolution of investigator-reported sVOCs post-engraftment. The safety profile of the BEAM-101 treatment regimen is consistent with busulfan conditioning, autologous HSCT, and underlying SCD. These results demonstrate the potential for base editing of the HBG1/2 promoters as a safe and effective therapeutic modality for the treatment of SCD that also has the potential to minimize hospitalization and treatment process burden for patients, families, and sites.

Abstract Introduction: Only 30% of patients (pts) presenting with abnormal bleeding symptoms receive a clear diagnosis, with many classified as having bleeding disorder of unknown cause, or BDUC (Baker et al. 2021). Currently, the recommended diagnostic workup for BDUC by the International Society on Thrombosis and Haemostasis (ISTH) includes plasmatic assays for coagulation factors, von Willebrand factor (vWF) antigen/activity, and platelet function testing (PFT), specifically platelet function analyzer-100 (PFA-100) and light transmission aggregometry (LTA). However, PFTs are not widely available and cannot be mailed to reference laboratories. We studied the diagnostic yield of an expanded testing panel which includes quantitative platelet glycoprotein flow cytometry (GpFL) and platelet electron microscopy (PTEM), which we have optimized for specimen mailing. Methods: We conducted a minimal risk, retrospective study by reviewing the electronic health records of pts (18 years and older) who were seen in the Coagulation Clinic of a tertiary academic medical center for evaluation of a bleeding disorder between October 2017 and June 2025. Testing included plasma-based assays including PT, APTT, vWF assay, FVIII, FIX, FXIII screen, and thrombin time (and additional reflex assays as needed). At the discretion of the treating clinician, PFTs (PFA-100 and LTA), GpFL, PTEM, and fibrinolysis assays (plasminogen activator inhibitor-1 antigen [PAI-1 Ag] and alpha-2 plasmin inhibitor) were included. We abstracted clinical data on pt demographics, ISTH bleeding scores, and the results of coagulation testing. Pts with an established diagnosis of a bleeding disorder, underlying malignancy, and those who did not have plasma-based coagulation testing were excluded from this study. Results: 109 pts met study criteria, and 82.6% were females (n = 90) with a median age of 45 years (range = 18-88 years). The median ISTH-BAT score was 7 (range: 2-21). About half of the pts, 49.5% (n = 54), had normal coagulation profiles and PFTs. All 54 had PTEM performed, of which 14.8% (n = 8) were abnormal (alpha and/or dense granule deficiencies). 85.2% (n = 46) had GpFL testing performed, with one showing reduced Gp2b/CD42 and Gp3a/CD61 expression, four showing reduced Gp1a/CD49b expression, and three showing reduced GpVI expression. Half of the pts, 50.5% (n = 55) had an abnormal coagulation profile from plasma and/or PFTs, of which 20% (n = 11) had a clinically significant coagulation factor deficiency (FV, FVII, FX). Roughly 9.1% (n = 5) had type 1 vWD of which 1 also had PAI-1 deficiency. One pt had isolated PAI-1 deficiency. Abnormal coagulation profiles were noted in 53 pts who had PFA-100 and LTA done, and both tests were normal in 22.6% (n = 12). Within the abnormal coagulation profile group, 10.9% (n = 6) had ultrastructural abnormalities on PTEM (dense and alpha granule abnormalities). Majority of the pts (n = 46) had GpFL done, and one had abnormal reductions in Gp1b-aCD42b, three in Gp1aCD49b, and seven in GPVI. Comparison of the ISTH BAT score between the normal and abnormal coagulation profiles/PFTs groups by non-parametric (Mann-Whitney U test) and parametric (Welch's t-test) showed no significant difference (p = 0.56 and p = 0.87) respectively. Conclusion: In this cohort of pts with abnormal bleeding, standard recommended testing resulted in a diagnosis in 66.4% pts. The remainder would have been classified as BDUC. The addition of GpFL and PTEM resulted in establishing a diagnosis that explains the bleeding phenotype in 14.8% of pts with an otherwise normal coagulation profile and PFT. Although abnormal PFTs indicate a platelet function defect, GpFL and PTEM may further define the abnormalities particularly differentiating syndromic from non-syndromic inherited platelet disorders. Additional studies are needed to confirm our findings and explore the possibility of addition of GpFL and PTEM for patients with BDUC.

Abstract Background: Partial tandem duplications of the histone methyltransferase KMT2Agene(KMT2A-PTD) are the most common KMT2A-aberration in adult acute myeloid leukemia (AML). KMT2A-PTD AML represents a high-risk disease subset with a poor prognosis. However, KMT2A-PTD leukemia is under studied, likely due to a lack of experimental models, and therefore the underlying mechanisms of leukemogenesis remain elusive. Since KMT2A-PTD leukemias possess high-level expression of HOXAgenes, similar to KMT2A-rearranged (KMT2A-r) and NPM1c AML, patients with this type of AML are currently enrolled into several phase I/II trials assessing menin inhibitors (MIs). However, mechanistic or clinical evidence for treatment response is lacking. To date, no targeted therapeutic approaches for KMT2A-PTD leukemia are available. Results: To better understand KMT2A-PTD mediated leukemogenesis, we endogenously tagged the KMT2A-PTD or KMT2A-wildtype (WT) allele in EOL-1 cells with a dTAG that can be degraded with PROTACs. Targeted protein degradation showed that the KMT2A-PTD, but not the KMT2A-WT protein, is critical to maintain leukemia cell growth. We identified KMT2A-PTD specific genome-wide chromatin binding sites and direct target genes as assessed by changes in nascent RNA production that started to occur within 30 minutes of KMT2A-PTD degradation. KMT2A-PTD target genes identified in this study included HOXA9, HMX2, HMX3, CDKN2C, MYC and CDK6 among others. Having defined the KMT2A-PTD target gene program, we assessed the effect of MI on KMT2A-PTD function. In KMT2A-PTD cell lines, PDXs and cells from a published murine KMT2A-PTD/FLT3-ITD knockin model, we observed intrinsic resistance to revumenib characterized by retained chromatin binding of KMT2A-PTD, but not KMT2A-WT after MI treatment. We next defined critical domains for KMT2A-PTD function via a KMT2A domain scan. This revealed the CXXC domain and AT hooks as critical dependencies in EOL-1 cells. Overexpression of KMT2A or mutants with duplicated domains in 293T cells showed that a duplication of the CXXC domain or the AT hooks is sufficient to mediate retained KMT2A chromatin binding under MI. Therefore, the resistance to MIs is likely due to the duplicated protein of KMT2A subverting menin function at critical target loci. Given that KMT2A-PTD remains chromatin-bound upon menin inhibition, we focused on ENL as a potential regulator of leukemia gene expression programs. In KMT2A-r and NPM1c leukemia, the ENL protein has been shown to be a critical dependency as it associates with acetyl lysine via its YEATS domain. ENL/AF9 YEATS inhibitors reverse ENL-dependent gene expression including HOXA9 and MYC. Using the small molecules TDI-11055 and TM-7, we show that YEATS inhibition leads to loss of members of the super-elongation complex and DOT1L from KMT2A-PTD driven loci and downregulation of target gene expression. Treatment of KMT2A-PTD PDXs with YEATS inhibitors induced differentiation and significantly reduced leukemia burden in vivo. Interestingly, we show that in contrast to previous findings in KMT2A-r leukemia, loss of ENL alone is insufficient to abrogate leukemic proliferation of EOL-1 cells. Instead, by combining ENL degradation with CRISPR-Cas9 mediated knockdown of AF9, we find that both YEATS proteins, ENL and its paralogue AF9, support aberrant gene expression in KMT2A-PTD leukemia. Finally, we show that the novel combination of MI and YEATS inhibition (revumenib plus TDI-11055) synergistically affects proliferation and induces differentiation in cell line and PDX models of KMT2A-PTD leukemia, which in turn prolongs survival of mice with KMT2A-PTD leukemia. Conclusions: KMT2A-PTD leukemia is dependent on the mutated, but not the WT KMT2A allele. It is characterized by a relative, intrinsic resistance to MI monotherapy, which is mediated by a duplication of the CXXC domain and AT hooks of KMT2A. Targeting both, the ENL and AF9 YEATS domain, is a possible treatment strategy and when combined with revumenib, YEATS inhibition has synergistic effects and overcomes intrinsic MI resistance. However, based on our studies, MI monotherapy may not be effective for most patients with KMT2A-PTD leukemia. Given that numerous compounds targeting the ENL (and AF9) YEATS domain are under study and MIs have recently obtained FDA approval, the combination of MI and YEATS inhibition could be translated into clinical trials for patients with KMT2A-PTD leukemia in the relatively near future.

Abstract Introduction: Nucleophosmin 1 mutations (NPM1-m) drive leukemogenesis in approximately 30% of acute myeloid leukemia (AML) cases. Ziftomenib is a potent, highly selective, oral, investigational menin inhibitor that has demonstrated clinical activity as both monotherapy and in combination for adults with NPM1-m or lysine methyltransferase 2A-rearranged (KMT2A-r) AML. KOMET-007 (NCT05735184) is an ongoing, open-label, dose-escalation (phase 1a) and expansion (phase 1b) study of ziftomenib in combination with standard chemotherapies in NPM1-m or KMT2A-r AML. Here we present phase 1b safety and clinical activity in patients with newly diagnosed NPM1-m AML who received the recommended phase 2 dose (RP2D) of ziftomenib 600 mg in combination with venetoclax and azacitidine (Ven/Aza). Methods: Adults (≥18 years) with newly diagnosed NPM1-m AML who were not eligible for intensive chemotherapy were enrolled in phase 1b and received ziftomenib 600 mg once daily plus standard doses of Ven/Aza. Ziftomenib was orally administered once daily continuously from Cycle 1 Day 8 onward. Phase 1b primary endpoints were adverse events (AEs) and complete remission (CR) per ELN 2022. Secondary endpoints included composite CR (CRc; defined as CR with full, partial, or incomplete hematologic recovery), overall response, and duration of response. Local measurable residual disease (MRD) was assessed by next-generation sequencing, RT-qPCR, and multiparameter flow cytometry. Results: As of June 25, 2025, 39 patients with newly diagnosed NPM1-m AML were enrolled and treated with ziftomenib 600 mg once daily plus Ven/Aza in phase 1b. Median age was 75 years (range 53–93), 54% were female, 46% had ECOG PS 0–1; 12 (31%) had FLT3 co-mutations and 9 (23%) had IDH co-mutations. Median duration of follow-up was 16.3 weeks (range 1.6–41.1). Twenty-nine patients (74%) had grade ≥3 treatment-emergent AEs, most commonly (≥20% of patients) decreased neutrophil count (31%) and decreased platelet count (23%). Grade ≥3 ziftomenib-related AEs occurred in 14 patients (36%), most commonly decreased neutrophil count (15%) and decreased platelet count (13%). No ziftomenib treatment discontinuations occurred due to AEs. Differentiation syndrome occurred in 1 (3%) patient (grade 2), which successfully resolved with protocol-specified mitigation. One patient (3%) had investigator-assessed ziftomenib-associated QTc prolongation (grade 3); however, there were concomitant significant electrolyte abnormalities and event resolved with electrolyte repletion. At time of data cutoff, 31 NPM1-m patients were response-evaluable (≥1 response assessment or death). CRc rate was 84% (26/31) after a median time to first CRc of 3.5 weeks (range 2.4–9.4), with local MRD-negativity rates among tested CRc responders of 54% (13/24) after a median time to first MRD-negativity of 8.4 weeks (range 2.9–17.4). CR rate was 58% (18/31) and overall response rate was 94% (29/31), with responses and MRD-negativity rates continuing to evolve. During continuous ziftomenib administration in patients who achieved CRc, median time to neutrophil recovery (≥1×109/L) was 36 days, and median time to platelet recovery (≥100×109/L) was 28 days. The median duration of response and median overall survival were not reached as of the data cutoff, at a median follow-up of 16.3 weeks. The study is ongoing, with 81% (25/31) of NPM1-m patients still on-study and 77% (24/31) still on ziftomenib treatment. Updated safety and clinical activity results will be presented.Conclusions: In the ongoing KOMET-007 study, ziftomenib RP2D of 600 mg once daily combined with Ven/Aza was well tolerated and demonstrated robust clinical activity in patients with newly diagnosed NPM1-m AML, including 84% CRc after a median of 3.5 weeks and 54% CRc MRD-negativity after a median of 8.4 weeks. Low rates of ziftomenib-related cytopenia and no additional myelosuppression were observed with this combination. One case each of differentiation syndrome (grade 2) and investigator-assessed QTc (grade 3) were successfully resolved. Taken together, these data support the RP2D determination and advancement of this ziftomenib-based combination in the KOMET-017 (NCT07007312) randomized phase 3 study in patients with newly diagnosed NPM1-m AML.

Abstract Introduction Nadir bone marrow biopsies (BM Bx) are routinely performed around day 14 to assess early response to AML intensive induction therapy. The presence of residual disease prompts initiation of reinduction therapy, often with another cycle of intensive chemotherapy. Whether there are characteristics of nadir BM Bx that predict for response to intensive reinduction is unknown. To evaluate this, we analyzed data from ECOG-ACRIN clinical trials in AML of intensive induction chemotherapy with nadir biopsy information available to determine predictors of outcomes after reinduction. Methods We included patients from ECOG-ACRIN E1900 (Fernandez NEJM 2009) and arm A of E2906 (Foran ASH 2015) who received induction therapy with daunorubicin and cytarabine (7+3), had residual disease (blasts ≥5% or cellularity ≥20%) at nadir BM Bx and received reinduction chemotherapy. Nadir BM Bx characteristics that were evaluated included blast percentage and cellularity as well as both absolute and relative (percentage change, e.g. 20% to 10% = -50%) differences calculated between diagnosis and nadir for each parameter. Complete remission (CR) after reinduction therapy, disease free survival (DFS) and overall survival (OS) were outcomes for all analyses. Logistic regression models were used to evaluate associations with CR, and Cox proportional hazards models were used for DFS and OS. For models evaluating changes in blast percentage or cellularity as predictors, baseline blast percentage or cellularity was included as a covariate, respectively. Results Of 1013 patients identified, 750 (74%) had a nadir biopsy, 233 (23%) had evidence of residual disease, received reinduction therapy, and were included in the primary analysis. The median age was 58 and 42% were female. Cytogenetic risk category (by ELN2017) was adverse in 31%, intermediate in 66% and favorable in 3%. The median nadir BM Bx blast was 30% (range 0 to +97%) and cellularity was 20% (0 to +100%). The median absolute difference in blast percentage between baseline and nadir BM Bx was -15% (-95% to +66%) with a median relative difference of -36% (-100% to +400%). After reinduction, 118 patients (52%) achieved a CR. Neither absolute difference in blast percentage (OR 0.99, 95%CI 0.98-1.00, p=0.20) nor relative difference (OR 1.00, 95%CI 0.99-1.00, p=0.33) predicted CR. There was similarly no association with DFS (HR = 1.00, 95%CI: 0.99-1.01, p=0.65) or OS (HR = 1.00, 95%CI 0.99-1.01, p=0.76). Blast reduction ≥50% similarly did not predict these outcomes. We also evaluated the impact of any reduction in blast percentage (responders) from baseline to nadir and again found no association with CR (OR 1.65, 95%CI 0.90-3.03, p=0.11). Similarly, there was no association with DFS (HR 0.74, 95%CI 0.51-1.09, p=0.13) or OS (HR 0.81, 95%CI 0.58-1.13, p=0.21) in responders vs nonresponders. No association with CR, DFS or OS were identified when performing the same analysis in intermediate and adverse cytogenetic subgroups. We found no association with CR when nadir cellularity was assessed as a continuous variable (OR 0.99, 95%CI 0.98-1.00, p=0.10) or by relative difference (OR 0.99, 95%CI 0.99-1.00, p=0.10). There was a trend towards association with absolute reduction in cellularity from baseline to nadir and CR (OR 0.99, 95%CI 0.98-1.00, p=0.06). No association was identified between relative difference in cellularity and DFS and OS, nor was there an association among cytogenetic risk subgroups with any outcome. Discussion In intensively treated patients with residual disease at nadir BM Bx (i.e. day 14) who received intensive reinduction, the likelihood of achieving a CR was not influenced by the magnitude of disease reduction nor the extent of disease at the time of nadir biopsy. Similarly, there were no nadir biopsy features that predicted DFS or OS after intensive reinduction therapy. Given alternative reinduction therapies such as hypomethylating agents and venetoclax are available, these results suggest that the decision to attempt a second intensive induction cycle following the unequivocal presence of residual disease should not be influenced by characteristics of the nadir BM Bx. Although patient-specific factors such as patient fitness may favor a switch to less intensive options, these results support consideration of intensive reinduction therapy in patients with residual disease at nadir biopsy, even without changes in blasts or cellularity.

Abstract Diffuse Large B Cell Lymphoma (DLBCL), the most common subtype of aggressive B-cell Non-Hodgkin Lymphoma (NHL), accounts for 30-40% of newly diagnosed NHL cases. Despite recent progress improving our understanding of molecular features of DLBCL, there is still a high relapse rate (~45%) among patients who undergo standard treatment (R-CHOP). Several groups have identified reproducible molecular clusters of DLBCL although, the biologic significance of many of the specific gene mutations within these clusters is poorly understood. DTX1 mutations are a feature of the BN2/C1 DLBCL classifiers and are among the mutations with unknown significance. BN2/C1 DLBCL are a mixture of ABC, GCB, and Unclassified cell of origin (COO) with a common signature being the presence of genetic alterations in genes known to regulate the NOTCH pathway; yet, these tumors lack transcriptional signatures of traditional NOTCH activation, suggesting a unique and undefined biology driven through non-canonical NOTCH pathway activation. DTX1 is an E3 ubiquitin ligase which directly binds the intracellular domain of the NOTCH receptor (NICD), targeting it for degradation, resulting in suppression of NOTCH pathway activity. We therefore hypothesize that DTX1 mutations lead to NOTCH pathway dysregulation and are a critical driver for a subset of BN2/C1 DLBCLs. Using whole exome sequencing (WES) data from 404 newly diagnosed DLBCL patients, we found 8% of patients with mutations in DTX1. Alterations in DTX1 were localized to the NICD binding domain, WWE1. In silico Alphafold modeling of DTX1 WWE1-interaction with NICD revealed that patient mutations clustered within predicted interacting surfaces with NICD. These findings lead to the hypothesis that mutations in the DTX1 WWE1 domain suppress its ability to bind to and degrade NICD, enhancing NOTCH pathway activation in DLBCL. To address this question, we first compared DTX1 protein expression by immunoblot in DTX1 WWE1 mutant (OCI-Ly3 and SUDHL2) and wildtype (WT) (OCI-Ly7, OCI-Ly19, SUDHL6, and U2932) DLBCL cell lines. We found higher expression of NICD1 (p=0.03) in OCI-Ly3 and NICD2 (p<0.0001) in SUDHL2 cell lines compared to WT. This increase was accompanied by an increase in NOTCH surface expression with higher NOTCH1 (p<0.0001) and NOTCH2 (p<0.0001) expression on OCI-Ly3 and SUDHL2 cells, respectively, compared to WT. To remove variability across cell lines we next used CRISPR to generate DTX1 knock out (KO) models using WT DTX1 DLBCL cell lines U2932 and OCI-Ly19. Analysis of NICD and NOTCH receptor protein expression confirmed our initial finding, showing an 8.5 and 4.8-fold increase of NICD1 and a 6 and 2.5-fold increase of NICD2 expression in the U2932 and OCI-Ly19 DTX1 KO cell lines, respectively, compared to empty vector (EV) controls. An increase in surface NOTCH1, and to a lesser extent NOTCH2, was seen in U2932 (p=0.01 and p=0.07, respectively) and OCI-Ly19 (p=0.001 and p=0.2, respectively) KO cells compared to EV controls. To identify pathways affected by DTX1 mutations, we next performed RNAseq on U2932 EV and KO cell lines. Of interest, we did not detect any significant changes in classical NOTCH driven genes (Hes1, Hey1, etc.), supporting prior studies on BN2/C1 tumors. However, we did identify potential non-canonical NOTCH-target genes that may contribute to lymphomagenesis. Gene expression in KO cells showed upregulation of genes involved in germinal center (GC) processes (AICDA, IRF4; p<0.001) and cellular growth and survival (IL6R, CCND2, STAT5B, BCL2; p<0.0001). Measurement of IL6R by flow cytometry and CyclinD2 by immunoblot further verified DTX1-mediated upregulation of IL6R (p<0.01) and CyclinD2 (p<0.01) for U2932 KO cells compared to EV control. We also observed downregulation of genes contributing to cell death (ex. BAX, CASP8, FAS; p<0.05) in KO cells compared to EV. Together, these novel findings support our hypothesis that DTX1 WWE1 mutations lead to dysregulation of the NOTCH pathway by driving overexpression of NICD and NOTCH, resulting in dysregulated expression of proteins involved in cell cycle, GC reaction, and apoptosis. We further provide new biologic insight into BN2/C1 DLBCL, ultimately highlighting a path toward novel therapeutic targets and the advancement of personalized medicine, as patients harboring these mutations may benefit from new therapies targeting inflammatory pathways, such as CELMoDs.

Abstract Introduction: CD19-directed CAR T-cell (CAR-T) therapy has substantially improved clinical outcomes for adults with relapsed or refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL). However, notable toxicities are associated with CAR-T, including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS). Variable practice patterns have emerged regarding the use of CRS/ICANS prophylaxis (ppx) via corticosteroids and/or other pharmacologic agents, but the utility of these approaches on reducing CRS or ICANS following CAR-T in B-ALL remains unknown. Thus, we utilized the Real-World Outcomes Collaborative for CAR T in ALL (ROCCA) database to evaluate associations between ppx and the development and severity of CRS or ICANS following brexucabtagene autoleucel (brexu-cel) for B-ALL. Methods: Adult patients (pts) who received standard-of-care brexu-cel for relapsed/refractory B-ALL across 40+ US centers were included. Primary endpoints were the incidence of CRS and ICANS within 28 days of CAR-T infusion. Secondary endpoints included timing of CRS and ICANS onset, progression-free survival (PFS) and overall survival (OS). Univariable and multivariable logistic regression evaluated associations between ppx and incidence of CRS/ICANS; KM and log-rank methods were used for survival analyses. Results: A total of 378 pts were included: 53 pts (14.0%) received CRS/ICANS ppx and 325 (86.0%) received no ppx. Ppx agents included steroids only (26.4%), steroid and anakinra (52.8%), anakinra only (15.1%), and steroid and tocilizumab (5.7%). Pts in the ppx group had a higher proportion of Hispanic pts (64% vs 34%), Ph-like (36% vs 19%) and a lower proportion had 0-5% bone marrow blasts at apheresis (38% vs 53%). The ppx and no ppx groups were similar in age, prior therapies, CAR-T indication, and marrow blasts >50%. Cumulative incidence of any grade (gr) CRS was 94% with ppx and 86% with no ppx (p=0.025), of any gr ICANS was 53% with ppx and 51% with no ppx (0= 0.85). Cumulative incidence of gr 3-4 CRS was 9% in the ppx group and 10% in the no ppx group (p=1.00), of gr 3-4 ICANS was 26% in the ppx group and 29% in the no ppx group (p=0.71). Median time to onset for any gr CRS or any gr ICANS was identical in the ppx and no ppx cohorts (CRS: 5 days, range ppx 1-9 days, no ppx 0-14 days; ICANS: 7 days, ppx 1-20 days, no ppx 0-16 days). Univariate logistic regression analyses showed no significant association between ppx and the incidence of gr 2-4 CRS (OR 1.34, 95% CI: 0.75-2.40, p=0.326) or gr 3-4 ICANS (OR 0.88, 95% CI: 0.46-1.70, p=0.708). Multivariate analysis adjusting for ethnicity, leukemia genetic sub-type, and pre-apheresis disease burden similarly found no significant associations between ppx and gr 2-4 CRS (adjusted OR 1.06, 95% CI: 0.55-2.01, p=0.870) or gr 3-4 ICANS (OR 1.23, 95% CI: 0.59-2.55, p=0.584). When comparing steroid-only ppx (N=14) to steroid combinations or other drug ppx (N=39), there was no significant differences in gr 2-4 CRS (57% vs 44%, p=0.345) or gr 3-4 ICANS (43% vs 21%, p=0.115). Comparing cumulative incidence of dexamethasone (dex) exposure, pts in the ppx group had numerically greater dex exposure than pts in the no ppx group, with median (range) dosing of 182 mg (10-1386mg) and 100mg (1-4000mg), respectively. Finally, we found no significant differences in PFS or OS based on ppx. Median PFS was 9.6 months in the ppx group vs 13.3 months in the no ppx group (p=0.646) and median OS was 17.2 months in the ppx group vs 34.4 months in the no ppx group (p=0.170). Conclusions: In this large cohort of adult patients with R/R ALL receiving brexu-cel CAR-T therapy, prophylaxis intended to prevent CRS/ICANS was ineffective at reducing CRS/ICANS incidence, time to onset, or overall steroid exposure. Furthermore, PFS and OS were comparable between patients who received prophylaxis and those who did not. In the absence of prospective trials in B-ALL, these data suggest that current strategies of CRS/ICANS prophylaxis has limited benefit.