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Background: The anti-apoptotic protein Mcl-1 contributes to the pathophysiology of certain B-cell malignancies and AML, and dependence on Mcl-1 is associated with resistance to venetoclax. Efforts to target Mcl-1 through direct inhibition have faced challenges due to cardiovascular toxicities. Voruciclib, a potent oral CDK9 inhibitor (CDK9i), was shown to indirectly downregulate Mcl-1 protein levels and synergize with venetoclax in preclinical models in lymphoid and myeloid malignancies. In solid tumors, voruciclib maximum tolerated dose (MTD) was defined as 350 mg with continuous daily dosing, and 600 mg when used on days 1-14 on a 21-day cycle. This phase 1 study is the first to evaluate the safety, dose-limiting toxicities (DLT), preliminary efficacy, pharmacokinetics, and pharmacodynamics of voruciclib in R/R hematologic malignancies (NCT03547115). Methods: Patients (pts) with relapsed B-cell NHL, CLL, or AML aged ≥18 years who had ECOG performance status ≤1, disease progression after standard therapies, adequate hepatic and renal function, and no prior CDK9i were eligible. The study followed a 3+3 design and DLTs were assessed in Cycle 1. Voruciclib was administered daily continuously at a starting dose of 50 mg on a 28-day cycle (Cohort I). After 2 DLTs were observed at 100 mg in AML pts, dosing was changed to daily on days 1-14 on a 28-day cycle (Cohort II). Also, pts with prior allogeneic transplant were excluded and dose escalation (100, 150, 200 mg) proceeded separately in AML and B-cell malignancies. Disease response was assessed by investigators using the Lugano, 2008 iwCLL, and 2017 ELN criteria. Results: 40 pts were enrolled: 21 AML, 19 NHL (9 DLBCL, 3 CLL, 3 MCL, 3 FL and 1 MZL). Cohort I enrolled 16 pts, 8 each at 50 mg and 100 mg. Cohort II enrolled 24 pts (17 AML and 7 B-cell malignancies), including 6 at 100 mg, 7 at 150 mg, and 11 at 200 mg. Dose escalation in Cohort II did not reach the MTD and was stopped at 200 mg, a dose that achieved plasma concentrations sufficient for target inhibition. Median age was 70 years (range 40-90), 72.5% of pts were ≥65 years, and 77.5% had ECOG performance status = 1. Pts had a median of 3 prior therapies (range, 1-8). Median duration on drug was 5 weeks (range 1-22). Drug-related serious adverse events (AEs) were reported in Cohort I only. Two pts with AML had a DLT of Grade (Gr) 3 interstitial pneumonitis at 100 mg; both had had allogeneic transplant and active graft versus host disease, one of whom also had a concurrent Gr 3 differentiation syndrome. One pt with DLBCL at 50 mg had Gr 3 hypoxemic respiratory failure in Cycle 4. In Cohort II, no DLTs were observed and there were no non-hematologic Gr 3-5 drug-related AEs. In the overall population, the most common AEs were diarrhea (30%), nausea (25%), anemia (22.5%), fatigue (22.5%), constipation (17.5%), dizziness (15%) and dyspnea (15%) [Table 1). One pt with AML had Gr 3 hyperbilirubinemia. There was no evidence of drug-related neutropenia in pts with NHL. No significant cardiovascular AEs were observed. One pt with AML in Cohort I achieved a morphologic leukemia-free state. At 200 mg, 5 of 10 AML pts (50%) had stable disease. Voruciclib pharmacokinetics was dose proportional, mean accumulation ratio was 2.4, mean T max was 4 hours, and at 200 mg, steady state C max was 925 ng/mL and mean C trough was 442 ng/mL (~1 microM). Analysis of Mcl-1 protein expression in normal lymphocytes by flow cytometry showed a trend of decrease in on-treatment samples compared to pre-treatment. Consistent with this, RNA-Seq analysis of 3 paired CLL samples confirmed rapid (after 6 hours) downregulation of Mcl-1 mRNA transcript in the malignant B-cells. Furthermore, scRNA-Seq analysis of 2 longitudinal AML samples demonstrated downregulation of MYC transcriptional program and oxidative phosphorylation in circulating AML blasts, both evident 24 hours after start of voruciclib and ongoing at C1D15. Conclusions: Voruciclib at doses up to 200 mg administered on 14 consecutive days on a 28-day cycle was well tolerated, with no DLTs observed, and no cardiovascular toxicities. There was no significant myelosuppression in pts with B-cell malignancies. As the safety profile suggested non-overlapping toxicities with venetoclax, the study is now evaluating voruciclib in combination with venetoclax in pts with R/R AML to exploit dual inhibition of Bcl-2 and Mcl-1.

Background. Acute myeloid leukemia (AML) is a heterogenous disease that occurs primarily in older adults with a median age of 69 years at diagnosis. Most studies that characterize the genomic landscape of AML include younger adults with the majority of patients being younger than 60 years of age. We aimed to study the mutational landscape of newly diagnosed AML patients aged 60 years or older. Methods.Samples were collected from the multi-center Beat AML Master Trial (Burd, Nat Med 2020). Patients were enrolled between 2016 and 2023. Informed consent was obtained according to the Declaration of Helsinki. Patients diagnosed with non-APL AML and who were aged ≥ 60 years old were included. Patients underwent bone marrow aspiration and biopsy, cytogenetic analysis, FLT3-ITD ratio assessment (LeukoStrat CDx FLT3 Mutation Assay, Invivoscribe) and next generation sequencing (NGS) using FoundationOne®Heme(Foundation Medicine) to interrogate the entire coding region of 406 genes and select introns of 31 genes involved in rearrangements, as well as RNA sequencing to interrogate 265 genes known to be somatically altered in human hematological malignancies. The presence of multiple hotspot mutations within one gene in an individual patient was counted as one gene mutation. Patterns of co-occurrence between gene mutations were calculated using the Phi correlation coefficient. Statistical analyses were performed using R statistical software. P<0.01 was considered statistically significant. Results. A total of 1088 newly diagnosed AML patients were identified, of whom 1032 were 60 years or older. Patients had a median age of 72 years at time of diagnosis (range 60-92 years). Forty-two percent of the patients were female, most patients were non-Hispanic and 79% were Caucasian. NGS data were available for 1024 patients and mutations were identified in 461 different genes. Patients had a median number of 11.0 mutations (range 3.0 to 28.0). The most frequently mutated genes were DNMT3A (n=257; 25.1%), TP53(n=255; 24.9%), TET2 (n=243; 23.7%), RUNX1 (n=225; 22.0%), SRSF2 (n=221; 21.6%), ASXL1 (n=216; 21.1%), NPM1 (n=206; 20.1%), FLT3 (n=205; 20.0%), IDH2 (n=190; 18.6%), NRAS (n=208; 16.9%), PTPN11(n=104; 10.2%), STAG2 (n=101, 9.9% and IDH1 (n=99; 9.7%) (Figure 1A). FLT3-ITD was present in 98 (12.1%) of the 810 patients who were tested. Strongest significant co-occurrence was found between FLT3and NPM1 (n=103), STAG2 and ASXL1 (n=63), ASXL1 and RUNX1 (n=92), ASXL1 and SRSF2 (n=88), RUNX1 and SRSF2 (n=94), STAG2 and SRSF2 (n=51) and DNMT3A and NPM1 (n=92) (p<0.01). Pairwise negative correlations were observed between TP53 and NPM1 (n=6), TP53 and SRSF2 (n=17), and between NPM1 and RUNX1 (n=6) (p<0.01) (Figure 1B). The cytogenetic profiles and the full genomic landscape will be presented during the ASH meeting. Discussion. This is the largest study investigating the mutational profile in older adults with AML aged 60 years and older. Due to the 7-day screening period of the Beat AML study, patient selection was biased towards less-rapidly proliferative AML. We showed that the pattern of gene mutations was markedly different from other studies in AML that mainly included younger AML patients (Papaemmanuil, NEJM 2016; TCGA, NEJM 2013 ). The frequency of mutated TP53 was substantially higher in older AML patients, as was the occurrence of myelodysplasia-related gene mutations (e.g., SRSF2, RUNX1, ASXL1, STAG2, U2AF1, and SF3B1) and gene mutations in IDH1, IDH2 and TET2. In contrast, NPM1 mutation was less frequently mutated in older AML patients. Furthermore, we demonstrated that a large proportion (46%) of the AML patients older than 60 years of age do have a mutation that is potentially targetable for treatment ( FLT3 IDH1 IDH2 and NPM1). The high incidence of mutated TP53 and MDS-related gene mutations underscores the increased incidence of high-risk AML and the need for innovative personalized therapies in this older age group. Figure 1. A. Co-occurrence of the 15 most frequently mutated genes, and B. co-correlation between the 15 most frequently mutated genes. Blue indicates positive correlation, red indicated negative correlation. Only significant correlations (p<0.01) are shown.

Background: We previously reported that treatment with the anti-CD30 antibody-drug conjugate brentuximab vedotin (BV) in combination with the checkpoint inhibitors targeting CTLA-4 and/or PD-1 (ipilimumab (I) and nivolumab (N)) led to high overall response rates (ORR) and complete response (CR) rates in relapsed/refractory (R/R) Hodgkin's lymphoma patients in a Phase 1 ECOG-ACRIN sponsored clinical trial. As previously presented in the Phase 1 component of NCT01896999 (E4412), the ORR for the treatment arms were: BV+I 76%, BV+N 89%, and BV+I+N 82%, with CR rates of 57%, 61%, and 73% across the groups, respectively. This suggested that not all patients who responded derived equal benefit. Moreover, with a median follow-up of 2.24 years, the PFS of 1.1 year, NR, and 2.49 years across the groups suggest that even some patients who achieved CR progressed on or subsequent to treatment. Currently biomarkers have no ability to predict which patients will maximally benefit from these therapies. We investigated blood-based immune biomarkers mechanistically across all cohorts which may explain differential responses and guide future treatment decisions for R/R HL patients. Methods: Peripheral blood plasma for 54 of 61 (89%) patients evaluable for response was collected at up to 4 time points and tested for 92 immuno-oncology soluble analytes with Olink proximity extension assay and for antibody titers to 20 known tumor antigens by ELISA. Matching peripheral blood mononuclear cells (PBMC) were analyzed by CyTOF mass cytometry for major immune cell subsets and marker surface expression, and for T cell receptor diversity by Immunoseq®. Mixed effect linear models were used to identify significantly associated changes (P<0.05) related to treatment longitudinally within groups and to ORR between groups. Results: Analysis of plasma demonstrated durable increase in soluble plasma PD-1 and decreases in CCL17, ANGPT2, MMP12, IL13, and CXCL13 in N-containing regimens, and higher GZMA and CAIX in BV+I (P<0.05). Despite baseline heterogeneity in PBMC composition, we found durable increases in plasmacytoid dendritic cells (pDC) after N-containing treatments, and transient increases in plasmablasts and memory B cells, as well as early decreases in naïve CD4+ T cells and neutrophils across treatments. Treatment with BV+I+N demonstrated late increases in neutrophils, and changes in memory B cell markers. Clinical benefit analyses revealed that elevated soluble CD5, ADA, CXCL13, and CCL17 at baseline or after two treatment cycles were associated with worse ORR (P<0.05), and that a module of co-regulated soluble analytes at baseline, including MUC16, was associated with worse progression free survival (PFS) (P<0.05). NY-ESO-1 autoantibodies were more frequent in non-responders, and the top 10% of expanded TCR clonotypes were increased in responders after one treatment cycle (P<0.05). Conclusion: This data reveals differential immune activation based on treatment modality for patients with R/R HL receiving checkpoint-based regimens in combination with an ADC. Our data highlights potential tumor- and immune-derived predictive and pharmacodynamic biomarker candidates of response and resistance. These novel findings have relevance for R/R HL patients receiving immunotherapy and other immunotherapy combinations such as immuno-chemotherapy platforms. Prospective evaluation of these biomarkers in the Phase II component of this study, a randomized comparison of BV+N vs. BV+N+I which has completed adult accrual, is planned. Figure Legend Clinical responders and non-responder patient samples were analyzed using ELISA (auto antibodies), CyTOF (Cell populations), TCRseq (T cell clonality) and Olink (proteomics). The results showed that pDCs, Neutrophils and B-Plasmablasts increased with specific drug combinations independently of clinical response. While T Cell expansion was associated with clinical response, the increase of auto antibodies against NY-ESO-1 and circulating proteins CD5, ADA, MUC16, CXCL13, CXCL9 and CCL17 were associated with worse prognosis

Introduction: Brexucabtagene autoleucel (brexu-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for adults with relapsed or refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL). Blinatumomab is a CD19-directed bispecific T-cell engager that is also approved for r/r B-ALL, and often used as early salvage therapy. Data in the pediatric/AYA population suggest that patients who did not respond to blinatumomab may have inferior outcomes to CD19-directed CAR-T products compared to those who have achieved a response to blinatumomab or were blinatumomab-naïve (Myers et al. J Clin Oncol 2022). In this study, we evaluate the response to blinatumomab and subsequent response to brexu-cel in adults with r/r B-ALL. Methods: Retrospective data were collected from 25 centers across the U.S. as part of the real-world outcomes collaborative study of CAR-T in B-ALL (ROCCA). Consecutive patients treated with brexu-cel from 2021 to 2023 were categorized by blinatumomab exposure status. Those exposed were separated into “blinatumomab responders” (B-R), defined as patients achieving a CR/CRi in response to any number of cycles of blinatumomab, and “non-responders” (B-NR). Each cohort was compared for outcomes of interest. The primary outcome was CR/CRi rate at day 28 following brexu-cel administration. Secondary outcomes were duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Survival outcomes were calculated from day of brexu-cel infusion and were not censored for allogeneic hematopoietic cell transplantation or maintenance therapy. All living patients were censored at data cutoff on June 30, 2023. Survival comparisons were made by log rank test. Results: Among 152 patients who received brexu-cel, the median follow-up time was 8.4 months. Eighty-eight (57%) of 152 r/r B-ALL brexu-cel recipients had received blinatumomab prior to apheresis. The median number of pre-apheresis blinatumomab cycles was 2 (range 1-12). The baseline characteristics of B-R, B-NR, and blinatumomab-naïve (B-NV) patients were similar, including pre-apheresis disease burden and receipt of maintenance therapy following brexu-cel infusion (Table 1). Seventy percent (N= 62) of the blinatumomab-exposed patients were B-R, while 30% (N=26) were B-NR. Rates of CR/CRi at day 28 following brexu-cel infusion were similar between B-R, B-NR, and B-NV patients (79% vs 84% vs 78%, respectively). Most of these remissions were negative for measurable residual disease (MRD), with similar MRD negativity rates in the three groups (table 2). 1-year DOR and PFS were significantly higher in the B-NV group compared to B-R or B-NR (77% vs 49% vs 50%, p<.0001; 60% vs 37% vs 30%, p<.0001). B-NV and B-R had better 1-year survival compared to B-NR (71% vs 65% vs 32%, p<.0001). There were more CD19-negative relapses following brexu-cel in B-NR (29%) and B-R (18%) compared to B-NV patients (8%), although this was not statistically significant. Conclusions: Brexu-cel induced deep responses in a majority of adults with r/r B-ALL, irrespective of prior exposure or response to blinatumomab. Similar to data published by the pediatric CAR-T cell groups, our data draw speculation that adult patients who did not respond to blinatumomab experience shorter overall survival following brexu-cel compared to those who responded to or did not receive blinatumomab. This should be confirmed in a larger, prospective clinical trial. Because this analysis could not account for patients who achieved durable remission after blinatumomab, these differences may not reflect superiority of sequencing brexu-cel before blinatumomab. The higher number of CD19-negative relapses in the blinatumomab-exposed cohort add to the interest in pursuing strategies to address antigen escape following CAR-T cell therapy directed against a previously targeted antigen.

Healthcare inequities are often attributed to large-scale structural barriers for access to medical care or patient-medical staff interactions. However, the role of the electronic medical record (EMR) in perpetuating hidden biases has been poorly characterized. This passive form of sharing implicit biases with unknown readers may have profound ripple effects asynchronous in place and time from the note writer. This study aims to illustrate racial imbalances in ad hominem patient characterizations as documented by medical staff, regardless of role, in a large metro healthcare system. The use of certain potentially stigmatizing language in emergency department (ED) and inpatient notes for hematology/oncology patients was investigated. Retrospective chart review of four hospitals within a university network in a major metro area between 1/1/2019 - 6/30/2021 was undertaken. Patients ≥22 years old were included with two primary hypotheses in mind: 1) Negative terms are used more frequently for underrepresented minorities, and 2) words with shock value (i.e. curse words) are used more often than more general descriptors of these terms (e.g. “cursing” or “profanity”). Nine positive and twelve negative terms were evaluated, based on the authors' observations of their use in the EMR in past encounters (Table 1). Some were personal descriptors in which the ED or inpatient note writer would be less likely than outpatient providers to have a full sense of outpatient care or social determinants of health (e.g. compliant). Others were behavioral descriptions (e.g. hostile) or words with minimal medical relevance (e.g. curse words). If multiple notes in an encounter included the same word(s), the encounter was only analyzed once for each word to avoid word count inflation, though re-occurrences for the same patient in subsequent encounters were counted. Authors' manual data review using natural language processing software confirmed appropriate use of terms. Generalized estimating equations were used for race-based comparisons to account for same-patient clustered encounters. Odds ratios (OR) and 95% confidence intervals (CI) were calculated for self-reported demographic comparisons with White as the reference category. P≤0.05 was considered significant. A total of 1,059 encounters for 889 hematology/oncology patients were analyzed. Mean age was 61 years (standard deviation 16.7) and 49.4% were female. White race was reported for 80.2% of patients (72% system-wide prevalence during same timeframe) and Black for 11.4% (15.2% system-wide); all others were ≤4% so only White/Black comparisons were included. Positive terms were more prevalent than negative ones (n=535 vs 459). However, negative terms were found more often for Black individuals (OR 2.24, CI 1.41 - 3.56, P<0.001), while the positive terms were less frequently documented in Black patients relative to White patients (OR 0.51, CI 0.33 - 0.77, P=0.001), and neither category was concordant with the overall patient racial demographics. Other significant racial differences existed for the terms “Argumentative”, “Disrespectful”, “Noncompliant”, and “Polite”, all discrepancies which favored White patients (Table 2). Specific curse words were documented nearly as often as “cursing”, “swearing”, or “profanity”, but no racial differences were observed. Some words in the initial search (“Brave”, “Courageous”, “Empathetic”, and “Ambitious”) were not found in hematology/oncology notes in this timeframe. EMR documentation in hospital-based hematology/oncology care demonstrated evidence of racial discrepancies in language that may carry stigma, positively or negatively. Importantly, many of these terms have questionable, if any, medical relevance. The use of stigmatizing terminology in the EMR may reflect implicit biases that extend past the direct patient encounter, passively and subconsciously prejudicing future care from other staff members. Time-saving heuristics and documentation shortcuts like copy-forwarding may further ossify healthcare inequities. This phenomenon is undoubtedly not limited to this hospital system or the hematology/oncology field, but quantitative real-world evidence has been scant. Improved awareness of stigmatizing language in documentation may be one step towards mitigating this contributor to unequal care for hematology/oncology providers and their patients.

Background: Emavusertib (CA-4948) is a novel oral inhibitor of interleukin-1 receptor-associated kinase 4 (IRAK4), which is essential for toll-like receptor (TLR) and interleukin-1 receptor (IL-1R) signaling in B cell proliferation. Additional inhibitory activity against FMS-like tyrosine kinase 3 (FLT3) and CDC-like kinases (CLK1/2/4) is also present in emavusertib. IRAK4 forms a Myddosome complex with MYD88 adaptor protein and drives overactivation ofnuclear factor-kappa B (NF-κB), causing inflammation and tumor growth. Emavusertib has been reported to be well tolerated and active as monotherapy in heavily pretreated patients with relapsed/refractory (R/R) non-Hodgkin lymphoma (NHL) (Nowakowski 2020). Preclinical studies demonstrated that tumor resistance and survival via IRAK4 activation could be delayed or reversed. Emavusertib crossed the blood-brain barrier in a murine PDX model of PCNS lymphoma, blocked the activated IRAK4 pathway, and induced tumor response and prolonged survival (von Roemeling 2022). In combination with Bruton tyrosine kinase (BTK) inhibitors, emavusertib showed in vitro synergy and re-sensitization of resistant cell lines, overcoming BTK resistance (Guidetti 2023a and 2023b). In vivo synergy in B-cell NHL was also demonstrated. Adaptive chemotherapy treatment resistance through IRAK4 upregulation and activation was also described in other disease models (Melgar 2019, Li 2019). This abstract presents preliminary efficacy and safety data of emavusertib + ibrutinib in R/R NHL patients. Aim:Assessment of safety and clinical activity of emavusertib in combination with ibrutinib. Methods: This is an ongoing open-label trial (NCT03328078) of emavusertib as monotherapy and in combination with ibrutinib. Part A1 - completed; dose escalation of emavusertib as monotherapy; the recommended phase 2 dose (RP2D) is 300 mg BID with continuous oral dosing (Nowakowski 2020). Part A2 - completed; dose escalation of emavusertib in combination with ibrutinib at 420 and 560 mg QD (Joffe 2022). Part B - ongoing; an expansion cohort of PCNSL patients with resistance to prior BTK inhibitors for additional safety and efficacy related to exposure: emavusertib at 100 or 200 mg BID + ibrutinib at 560 mg QD in 28-Day cycles. Results:As of 19 July 2023, 18 heavily pretreated NHL (including five PCNSL) patients received emavusertib at 100, 200, or 300 mg BID in combination with full ibrutinib doses per label. Median age was 63.5 years (range 50-92). Median number of prior lines of anti-cancer therapies was 3 (range 1-10). Eleven of 18 patients failed prior BTK inhibitors. Median treatment duration was 95.5 days (21-587 days), suggesting acceptable safety and tolerability. No DLTs were observed at the 200 mg BID dose level, and two reversible DLTs (stomatitis and syncope) were observed at the 300 mg BID dose level. The preliminary efficacy data of 16 evaluable patients in combination with ibrutinib showed 5 CRs (2 MCL, 3 PCNSL) and 1 PR (1 CLL). All 3 PCNSL patients with CR were previously treated with BTK inhibitors. Conclusion: The combination ofemavusertib plus ibrutinib (ema+ibr) is well tolerated with an acceptable long-term safety profile and promising efficacy, showing several objective responses in heavily pretreated and/or BTK inhibitor resistant patients. Emavusertib may have the potential to overcome BTK inhibitor resistance and the combination of ema+ibr has the potential to show increased anti-cancer activity compared to ibrutinib monotherapy.

Background: Axi-cel is an autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy approved for the treatment of relapsed/refractory (R/R) LBCL. ZUMA-12 (NCT03761056) is a Phase 2, multicenter, single-arm study of axi-cel as part of first-line treatment in patients with high-risk LBCL. In the primary efficacy analysis (n=37; median follow-up of 15.9 months), axi-cel demonstrated a high rate of investigator-assessed complete response (CR; 78%; 95% CI, 62-90) and an 89% objective response rate (ORR; 95% CI, 75-97). Axi-cel also had a manageable safety profile, with no new safety signals observed in the first-line setting (Neelapu et al. Nat Med. 2022). Here, we report updated efficacy and safety outcomes from ZUMA-12 in all patients treated with axi-cel after a median follow-up of ≥40 months. Methods: Eligible adults had high-risk LBCL, with MYC and BCL2 and/or BCL6 rearrangements (double- or triple-hit histology) per investigator or an International Prognostic Index (IPI) score ≥3, plus a positive interim PET per Lugano classification (Deauville score 4/5) after 2 cycles of an anti-CD20 monoclonal antibody and anthracycline-containing regimen. Patients underwent leukapheresis, followed by lymphodepleting chemotherapy (cyclophosphamide and fludarabine) on Days -5, -4, and -3, and a single axi-cel infusion of 2×10 6 CAR T cells/kg on Day 0. Per investigator discretion, non-chemotherapy bridging could be administered. The primary endpoint was investigator-assessed CR rate per Lugano classification (Cheson et al. J Clin Oncol. 2014). Secondary endpoints included ORR, duration of response (DOR), event-free survival (EFS), progression-free survival (PFS), overall survival (OS), safety, and levels of CAR T cells in blood and cytokines in serum. Results: As of May 3, 2023, 42 patients were enrolled and 40 were treated with axi-cel, with a median follow-up of 40.9 months (range, 29.5-50.2). In total, 37 patients were evaluable for response (centrally confirmed double- or triple-hit histology or IPI score ≥3). The CR rate was 86% (95% CI, 71-95), and 92% (95% CI, 78-98) of patients had an objective response. Patients with centrally confirmed double- or triple-hit histology (n=10) had a CR rate of 90%. Responses were ongoing in 73% of response-evaluable patients at data cutoff. Medians for DOR, EFS, PFS, and OS were not reached. The 36-month estimates for DOR, EFS (Figure 1), PFS, and OS (Figure 2) were 82%, 73%, 75%, and 81%, respectively. All treated patients (n=40) experienced adverse events (AEs) of any grade and 88% of patients had grade ≥3 AEs. Similar to the primary analysis, the most common any-grade AEs were pyrexia (100%), headache (70%), and neutrophil count decreased (55%). No new cases of cytokine release syndrome (CRS) or neurologic events of any grade occurred since the prior data cut and all cases of CRS and neurologic events reported were resolved by data cutoff. Prolonged cytopenias of any grade (present Day ≥30 post-infusion) occurred in 9 patients (n=7 neutrophil count decreased) and were resolved by data cutoff. There were 8 deaths due to progressive disease (n=5) and other causes not related to axi-cel (1 COVID-19, 1 esophageal adenocarcinoma, 1 septic shock on Days 350, 535, and 287 post axi-cel infusion, respectively). Two of the 8 deaths (1 progressive disease and 1 esophageal adenocarcinoma) occurred after the primary analysis. Among treated patients, post-infusion CAR T-cell expansion by peak and area under the curve was 36.9 cells/µL and 368.0 cells/µL×days, respectively, in those with ongoing responses at data cutoff (n=17), 45.1 cells/µL and 413.4 cells/µL×days in those who relapsed (n=6), and 34.7 cells/µL and 566.8 cells/µL×days in non-responders (n=3). Conclusion: In this updated analysis of ZUMA-12 with a median follow-up of ≥40 months, axi-cel demonstrated a high rate of durable responses and no new safety signals. Axi-cel may benefit patients exposed to fewer prior therapies and those with high-risk LBCL, a population with high unmet need and poor outcomes after standard first-line chemoimmunotherapy.

Background: Relapsed/refractory (R/R) Classic Hodgkin lymphoma (cHL) remains a significant clinical challenge. We hypothesized that using immune checkpoint blockade to activate the immune cells in the tumor microenvironment, and concurrently targeting tumor cells with the CD30 targeting antibody-drug conjugate brentuximab vedotin (BV) could overcome tumor resistance. E4412 is an intergroup Phase 1/2 ECOG-ACRIN sponsored study of the combinations of BV, nivolumab (N), and ipilimumab (I) in patients with R/R cHL. Here we present the efficacy and safety data on the full adult cohort of patients treated in Phase 2 randomized between BV/N and BV/N/I. Methods: Patients with confirmed R/R cHL were randomized between the doublet of BV/N with BV 1.8mg/kg and N 3mg/kg and BV/N/I with I 1mg/kg. BV and N were administered every 3 weeks, and I every 12 weeks for up to 1 year for BV and up to 2 years for N and I. Results: One hundred twenty-six patients were enrolled and treated; 8 patients (4 from each arm) were excluded from efficacy analysis based on ineligibility. Patients were not heavily pretreated, 65% had one prior line of therapy and an additional 27% had two prior lines, and 8% had more than 2 prior lines. The median age was 34; 51% of patients were male. Sixteen patients had prior BV: 10 (BV/N arm) and 6 (BV/N/I). Response: One hundred eighteen patients are evaluable for response: 61 treated with BV/N and 57 with BV/N/I. With BV/N 37 of 61 (60.7%) of patients had a complete response (CR) compared to 38 of 57 (66.7%) with BV/N/I for a difference of 6.7% (p-value 0.31). Additionally, 17 (28%) with BV/N and 12 (21%) of patients treated with BN/N/I had a partial response (PR) for an overall response rate (ORR) of 88% in both arms. In a planned analysis of patients with prior treatment with BV the CR rate was 25% in BV/N arm (2 of 8) and 60% in BV/N/I arm (3 of 5). The median follow-up for progression free survival (PFS), duration of response (DOR), and overall survival (OS) is 24.8 months and 33.7 months. The median PFS, duration of response and OS have not been reached for either arm with 24 months of follow-up ( Figure 1). In B/N 30 of 61 patients came off study to receive alternative treatments (primarily autologous stem cell transplant (SCT)) and in BV/N/I 23 of 57 patients did. Safety: Table 1 shows treatment-related Grade 3+ toxicity occurring in > 1 patient and adverse events (AE) of special interest. All 126 patients (118 eligible and 8 ineligible) are evaluable for safety. The rate of Grade 3+ treatment related toxicity is 43% (28/65) and 52% (32/61) for BV/N and BV/N/I, respectively. However, when rash is excluded the rate of treatment related toxicities is similar between the two arms 38.5% vs 39.3%. There was no grade 4 rash, and the rash was treatable in all cases with topical or oral steroids. There were no Grade 5 toxicities in either arm. Conclusion: In this randomized Phase 2 study comparing BV/N vs. BV/ N/I the difference in CR rate of 6.7% between the doublet and the triplet was not statistically significant. Additionally, the triplet had more grade 3 rash than the doublet, there was otherwise no significant difference in grade 3 or greater toxicity between the two arms. With a median follow-up of 24 months the PFS and DOR have not been reached for either arm, suggesting excellent disease control from both regimens. Differences in response for BV pre-treated patients between the two arms is intriguing especially as more patients are treated with BV in the frontline, but the sample size is too small to draw firm conclusions. Correlative studies are underway to elucidate a response vs. resistance signature, and biological understanding of differential benefit.

Introduction: Brexucabtagene autoleucel (brexu-cel) is an autologous anti-CD19 chimeric antigen receptor (CAR) T cell therapy approved for adults with relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL). Bridging therapy, defined as anti-leukemia therapy given between apheresis and lymphodepleting chemotherapy, was permitted on the pivotal ZUMA-3 trial. The optimal bridging therapy is unknown in this setting. Here we report patient and disease characteristics in those receiving bridging therapies prior to brexu-cel and the impact of bridging on clinical outcomes in a large multicenter cohort. Methods and Results: ROCCA includes 25 US institutions contributing retrospective data from 152 B-ALL patients treated with standard of care brexu-cel between 2021-2023. Ninety-nine patients (65%) received bridging therapy, while 53 patients (35%) received no bridging therapy. Bridging therapy consisted of cytotoxic chemotherapy ( n=65, 66%), immunotherapy ( n=26, 26%; 23 inotuzumab, 3 blinatumomab), tyrosine kinase inhibitors (TKI) ( n=20, 20%; 16 ponatinib), steroids only ( n=10, 10%), and intrathecal chemotherapy ( n=22, 22%). The median age of the cohort was 46 (IQR 32-61). Patients were heavily pre-treated with a median of 4 prior lines of therapy. The median days from apheresis to infusion was 33 (IQR 26-42). 119 patients had known pre-apheresis blast counts; the bridging group had higher pre-apheresis blast burden, with 21 of 76 patients (28%) having ≥ 50% blasts compared to only 5 of 43 patients (12%) in the no bridging group ( p=0.02). In addition, more patients who received bridging had pre-apheresis extramedullary disease (32% vs. 15%, p=0.02). All other baseline characteristics were similar between the two groups (Table 1). Fifty-four (54%) patients had response assessment after bridging therapy and prior to brexu-cel infusion. In patients who received inotuzumab for pre-apheresis active disease, defined as ≥ 5% blasts, 6 of 13 (46%) who had post-bridging assessment achieved a complete response (CR; 5 measurable residual disease (MRD)+, 1 MRD-), with a mean proportional reduction in blast burden of 46% from baseline. In contrast, after chemotherapy bridging, only 2 of 16 patients (13%) with pre-apheresis active disease had a CR. Patients receiving chemotherapy bridging had a mean proportional increase in blast burden of 4.4%. In recipients of TKI bridging, 2 of 4 patients (50%) with pre-apheresis active disease had a CR. Compared to no bridging, patients in the bridging group had similar rates of grade 3 or 4 CRS (9% bridging vs. 8% no bridging, p=0.73) and grade 3 or 4 ICANS (34% vs. 26%, p=0.32). In univariate analysis, there was no statistically significant difference in day 28 response with 63 patients (72%) achieving MRD- complete response in the bridging group as compared to 36 patients (78%) in the no bridging group ( p=0.60). Non-relapse mortality was similar between the two groups (17% bridging vs. 9% no bridging, p=0.20). Overall survival (OS) and progression-free survival (PFS) were superior in the no bridging group: 1-year OS 74.7% vs 56.8% (log-rank p=0.04), and 1-year PFS 57.3% vs 41.7% (log-rank p=0.04). In a multivariate analysis stratified by bridging and pre-apheresis disease burden, patients with pre-apheresis blasts ≥ 5% and bridging had worse survival than ≥ 5% blasts and no bridging: 1-year OS 45.3% vs. 87.5% and 1-year PFS 27.7% vs. 64.3% (Figure 1). However, patients with < 5% blasts had similar survival regardless of bridging. Conclusions: In our real-world analysis, adults with R/R B-ALL receiving bridging therapy had a higher disease burden at baseline. Despite greater baseline disease, there were no significant differences in toxicity and day 28 response in those receiving bridging therapy vs. not. While survival was inferior in patients with pre-apheresis active disease who received bridging, this may be confounded by the degree of tumor burden. In patients with < 5% blasts pre-apheresis, bridging did not impact survival. Furthermore, inotuzumab bridging demonstrated the most significant disease debulking. However, the comparisons in this study are limited by the variability in practice for post-bridging disease reassessment and the small proportion of patients with active disease who did not receive bridging. A more uniform approach to peri-CAR disease assessment would enable more robust study of optimal bridging strategies.

Background: BMT CTN 1703 was a Phase 3 trial comparing Tac/MTX (n = 217) to post-transplant cyclophosphamide (PT-Cy)/Tac/MMF (n = 214) GVHD prophylaxis after reduced intensity conditioning unrelated donor hematopoietic cell transplant (HCT). PT-Cy significantly improved GVHD-free Relapse-Free Survival (Bolanos-Meade et al NEJM 2023). However overall survival was not significantly different and the # of Grade 2 infections was higher with PT-Cy. To investigate its biologic underpinnings 1703 was linked to a mechanistic study, BMT CTN 1801, which co-enrolled 324 pts (159 CNI/MTX 165 PT-Cy). The resulting dataset enabled an analysis of post-HCT T cell reconstitution at an unprecedented level of detail. Methods: Samples were collected from the HCT infusion and on D+7, 14, 28, 63, 98, 180, 270, 1- and 2-yr. We extracted DNA (2,225 samples) and performed Adaptive Biotech β-strand T Cell Receptor (TCR) Immunosequencing (TCR-Seq). We profiled 44,077 (median) TCRs/sample resulting in 215,155,719 T cells analyzed. We evaluated multiple TCR diversity measures longitudinally and before/after cGVHD and infections. Each measure evaluates a specific aspect of TCR diversity, including Simpsons Clonality (focuses on the most expanded clones) Diversity Slope (mid-range clones) Richness (both mid-range and less-expanded clones) and Singletons (the TCR-Seq equivalent of naïve T cells). This analysis was robust to the full range (1000-50,000) of down-sampled TCRs sequenced. Results: We identified major differences in TCR reconstitution in Tac/MTX vs PT-Cy that begin early and persist through 2 yr post-HCT. These resulted in a significantly less diverse TCR repertoire with PT-Cy with substantial implications for its efficacy and toxicity. The most salient differences are: (1) PT-Cy caused significant in-vivo T cell depletion early post-HCT (% T cells/total WBC at D+28: 8.2% (Tac/MTX) vs 2.2% (PT-Cy) p=2.2x10 -23). (2) The remaining donor T cells in PT-Cy undergo substantial clonal expansion ( Fig 1) resulting in significantly constrained TCR diversity measured by Clonality, Slope, Richness, Singletons (not shown) and Singletons/Richness ( Fig 2) which began early (D+14) and persisted for 2 yr. (3) Linked T cell depletion and clonal expansion resulted in a TCR diversity bottleneck after PT-Cy ( Fig 1). Due to the bottleneck, while the fraction of T cells originating from the transplant infusion at =/> 1 yr was similar between arms (18% vs 24%, p=0.7) there were significantly fewer Singleton TCRs in PT-Cy, suggesting a reduction in naïve T cells ( Fig 2), an outcome that has critical consequences for both cGVHD and infection. Thus while cGVHD onset with Tac/MTX was linked to a significant drop in TCR diversity due to singleton clonal expansion (median log-2 fold change in singletons with Tac/MTX = -0.25 p = 0.01) this drop was not observed with PT-Cy (log-2 fold change = -0.05, p = 0.1). Along with the significantly decreased # singletons at all time-points in PT-Cy ( Fig 2) this suggests that while cGVHD after Tac/MTX is linked to substantial naïve T cell expansion, the same is not true with PT-Cy, identifying a novel mechanism for cGVHD control with PT-Cy. The substantially fewer singletons in PT-Cy vs Tac/MTX may also increase the risk of Grade 2+ infections. T cell responses to new infections rely on antigen recognition/effector maturation of naïve (singleton TCR) T cells. After infection, the TCR repertoire became less diverse for both Tac/MTX and PT-Cy (log-2-fold singleton change -0.17 and -1.2 p = 0.0006 and 0.01) indicating that singletons in both cohorts were capable of expanding to pathogens. However the markedly decreased # singletons in PT-Cy at all timepoints was associated with significantly fewer singletons prior to infection (mean 3979 at 5K read-depth for Tac/MTX vs 2820 for PT-Cy p<0.001). This singleton deficit would place PT-Cy patients at higher risk of missing the critical mass of TCRs required to respond effectively to infections, consistent with their increased rate of Gr 2 infections. Conclusions: We performed longitudinal TCR-Seq on >200 million T cells from 324 HCT patients, representing the largest post-HCT TCR-Seq analysis in the history of the field, and enabling novel insights into TCR dynamics. These data identify a previously unappreciated global TCR diversity bottleneck with PT-Cy that simultaneously protects patients from cGVHD and places them at higher risk of infectious complications.