O'Dwyer, Kristin

Abstract The use of chimeric antigen receptor (CAR) T-cell therapy is increasing for adult B-cell acute lymphoblastic leukemia (B-ALL), with 3 CD19 CAR T-cell products commercially available. Several key clinical questions related to best practices for CAR T-cell administration in this population exist, and limited prospective randomized trials have been conducted to fill these knowledge gaps. Thus, to help guide clinical practice, we conducted a modified Delphi study to develop and validate consensus recommendations on the administration of commercially available CAR T-cell therapy for adults with B-ALL. Consensus panelists (n = 9) included principal investigators (PIs) from Real World Outcomes Collaborative of CAR T-Cell Therapy in Adult ALL (ROCCA) consortium sites and were selected based on expertise and CAR T-cell center volume. Final panel consensus recommendations were distributed for rating by the remaining PIs from ROCCA consortium sites, which served as the validation group (n = 27). Consensus topics included patient selection, bridging and pre–CAR T-cell leukemia staging, lymphodepletion, and CAR T-cell treatment setting, specific toxicity prevention and management, post–CAR T-cell response assessment and disease monitoring, and the role of consolidation and/or maintenance therapies after CAR T-cell therapy. Initially, 58 recommendation statements were evaluated for consensus. After 2 panel meetings, a total of 34 statements achieved consensus rating among the expert panel. After rating by the validation group, all but 1 recommendation statement continued to meet consensus, for a total of 33 consensus recommendation statements on the administration of CAR T-cell therapy in adult B-ALL.

Abstract In a real-world analysis of brexucabtagene autoleucel recipients with relapsed/refractory B-cell acute lymphoblastic leukemia (N = 278), lack of response to prior blinatumomab correlates with significantly worse following chimeric antigen receptor T-cell therapy outcomes.

Abstract Introduction Obecabtagene autoleucel (obe-cel) and brexucabtagene autoleucel (brexu-cel) are CD19 targeted chimeric antigen receptor T cell (CAR-T) therapies, approved for the treatment of adults with relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (ALL). Mechanistic differences between obe-cel and brexu-cel including differing costimulatory domains (4-1BB vs. CD28), CD19 binding domains (intermediate vs. high affinity) and split dose (Days 1 and 10) vs. single infusion may impact in-vivo cellular kinetics that translate into variant clinical outcomes. In pivotal trials, obe-cel resulted in lower rates of severe cytokine release syndrome (CRS) and immune effector cell associated neurotoxicity syndrome (ICANS) compared to brexu-cel with comparable efficacy (Roddie et al., NEJM 2025; Shah et al., Lancet 2021). Real-world utilization and outcomes with obe-cel are unknown given the relatively recent approval. Methods The ROCCA database, comprising real world data from patients (pts) with r/r ALL treated at 40 North American institutions was utilized in this analysis. Pts with r/r ALL were eligible if they were apheresed for obe-cel since its approval (11/8/2024) or brexu-cel over a comparable period (since 8/1/24) and had at least 30 days of follow up. Data cut off was 7/15/2025. CRS/ICANS were graded per ASTCT criteria. Measurable residual disease (MRD) was assessed by flow cytometry and/or next generation sequencing per institutional standards. Results 38 pts have undergone apheresis for obe-cel (36 infused, all received both infusions) and 54 (53 infused) for brexu-cel over the study period. Pts in the obe-cel and brexu-cel cohorts had the following baseline characteristics: median age, 47 vs. 39 years; ECOG 2+, 15% vs. 26%; Ph+ disease, 24% vs 13%; KMT2Ar, 0 vs. 4%; TP53m, 11% vs 11%, and hypodiploid karyotype, 5% vs 6%. The following prior treatment patterns were observed: median lines of therapy before CAR-T 3 vs. 3; prior SCT 24% vs. 30%, prior blinatumomab 68% vs. 46%, prior inotuzumab 45% vs. 30%. At apheresis, active disease (>5% bone marrow blasts) was present in 47% vs. 55% of obe-cel and brexu-cel pts, respectively; the remainder were in CR (with 18% vs. 22% in MRD- CR, respectively). Among obe-cel (n= 35 [92% of cohort]) and brexu-cel (21 [38% of cohort] pts with disease re-assessment prior to lymphodepletion (LD), 31% vs. 43% had active BM disease, respectively; few pts (24% vs. 17%) had >20% marrow disease burden prior to LD. CAR-mediated toxicity differed significantly between the cohorts. CRS occurred in 56% of obe-cel pts compared to 94% of brexu-cel pts (p < 0.0001). There were no Gr3+ CRS events among the obe-cel pts; 3 (6%) brexu-cel pts had Gr3+ CRS (p = 0.27). ICANS occurred in 17% of obe-cel pts vs. 51% of brexu-cel pts (p = 0.001). Gr3+ ICANS occurred in 6% of obe-cel vs. 32% of brexu-cel pts (p = 0.0027). Among the obe-cel pts, CRS occurred in 31% after the first infusion and 46% after the second; ICANS occurred in 3% after the first infusion and 15% after the second. Prolonged Gr4 neutropenia (ANC < 500 cells/uL beyond day 30 from infusion) occurred in 24% of obe-cel vs. 28% of brexu-cel pts (p = 0.73). Deaths within the first 28 days of infusion occurred in 0 obe-cel pts and 4 brexu-cel pts (2 of infection, 1 of infection/brain bleed, and 1 of liver failure in the setting of Gr4 CRS and HLH). Response rates were high and did not significantly differ between cohorts (p = 0.85). Among the 31 obe-cel pts with available response data, 25 (81%) achieved an MRD- CR/CRi, 3 (10%) had an MRD+ CR/CRi, 2 (6%) had a CR/CRi with unknown MRD, and 1 (3%) did not respond. Among 41 brexu-cel pts with available response data, 33 (80%) had an MRD- CR/CRi, 4 (10%) an MRD+ CR/CRi, and 4 (10%) CR/CRi with unknown MRD. Conclusion Pts selected for obe-cel apheresis were similar to those for brexu-cel over the study period (noting that not all centers had access to obe-cel during this time). Similar to clinical trial results, obe-cel was associated with lower rates of CRS/ICANS. Rates of MRD-negative CR were high and did not differ between cohorts. A larger sample and longer follow up are required for further analyses; we anticipate a cohort of ~75 obe-cel treated pts by the annual meeting and will provide updated data.

Abstract Introduction: Brexucabtagene autoleucel (Brexu-cel) is a CD19-targeted chimeric antigen receptor (CAR-)T cell therapy approved for treatment of relapsed/refractory (r/r) B-ALL. Brexu-cel's approval was founded on data from the ZUMA-3 trial, in which 78 patients (pts) were treated at the pivotal dose of 1x10e6 CAR-T cells/kg, resulting in a complete remission (CR) rate of 73%. Three-year follow-up from ZUMA-3 demonstrated median relapse-free and overall survival (RFS/OS) of 11.6 and 25.6 months (mos) for all treated pts. Amongst responders, the median OS was 60.4 mos for those who did not receive a subsequent allogeneic hematopoietic cell transplant (HCT) (n=43), but only 36.3 months for those who did (n=14). This has led some to conclude that HCT may not be beneficial following brexu-cel therapy for r/r B-ALL; however, it must be noted that 29 (37%) of the pts treated on ZUMA-3 received brexu-cel for post-HCT relapse. T cells collected from individuals who relapse in the post-HCT setting are largely of donor origin, making the CAR-T product comparable to a genetically modified donor lymphocyte infusion (DLI). The immunology at play in this scenario may be different from that in which CAR-T cells are of truly autologous origin. Methods: The Real-World Outcomes Collaborative for CAR-T in ALL (ROCCA) consortium database includes pt characteristics and outcomes of brexu-cel therapy given as standard-of-care across 41 US institutions. We identified pts who achieved an MRD negative (neg) CR by either flow cytometry (minimum sensitivity 10e-4) or NGS following brexu-cel for r/r Ph neg B-ALL and categorized them into three groups with regard to use of HCT: Never HCT, Pre-CAR HCT, or Post-CAR HCT. Pts who received second HCT following brexu-cel for post-HCT relapse (n=9) were excluded. Pt/disease characteristics, RFS, and OS were assessed for each group, landmarked at 73 days after brexu-cel infusion (the median time to consolidative allogeneic HCT). Results: In the ROCCA database we identified 165 pts who achieved MRD neg CR following brexu-cel, amongst whom 69 never underwent HCT, 49 were transplanted pre-CAR (ie, brexu-cel served as a genetically modified DLI), and 47 underwent post-CAR consolidative HCT while in CR. The median follow-up is 373 days. The median age was higher in the Never HCT group (49, range 19-83) in comparison with the Pre-CAR HCT (40, 24-72) and Post-CAR HCT (34, 18-70) groups. Thirty-five percent were >60yo in the Never HCT group vs 20% in the Pre-CAR HCT and 9% in the Post-CAR HCT groups. Ph-like disease was present in 38%, 29%, and 43% of the Never HCT, Pre-CAR HCT, and Post-CAR HCT groups, respectively (p=0.35). No significant differences were observed in pre-apheresis bone marrow blasts, presence of CNS disease at apheresis, prior blinatumomab or inotuzumab treatment, or use of bridging therapy across the groups, though there was a higher prevalence of non-CNS extramedullary disease in the Pre- and Post-CAR HCT groups (32, 39%) vs the Never HCT group (13%) (p=0.004). A minority of pts in all groups were deemed to be in MRD neg CR prior to apheresis (6-20%). Median RFS was 260 days in the Never HCT group and not reached in the Pre- and Post-CAR HCT groups (p=0.002), with respective 1-yr RFS of 38%, 64%, and 67%. Median OS was not reached in any group and was similar for all at 1-yr at 68-79% (p=0.13). Characteristics of those in the Never HCT group who were least likely to relapse included age >60 (OR 0.22, CI 0.07-0.73 vs age 18-39, p=0.024) and those with non-Ph-like B-ALL (OR 0.33, CI 0.12-0.94, vs Ph-like, p=0.037) in univariate analyses. Conclusions: Real-world data regarding outcomes following brexu-cel therapy allow evaluation of the role for consolidative allogeneic HCT, which remains one of the most important unresolved questions in the use of CAR-T therapy for r/r B-ALL. This analysis demonstrates that a first consolidative HCT after achieving MRD neg CR with brexu-cel is associated with a significant decrease in relapse. Additionally, use of brexu-cel for post-HCT relapse is also associated with a significantly lower risk of relapse compared with those who never received an allogeneic HCT. With the current duration of followup, OS is not significantly different across the three groups. These data suggest there is a benefit for relapse-free survival in pts receiving an allogeneic HCT at some point in the course of treatment for r/r Ph neg B-ALL.

Abstract Background We performed a prospective study evaluating a baseline GA battery and clinical outcomes in fit older adults (age ≥60 years) with AML and normal cardiac and renal function in the recent E-A NCTN E2906 phase 3 study. A patient-reported outcomes (PRO) assessment of Depression, Activities of Daily Living (ADL), Cognitive Function, Social Support (SS) domains, and comorbidity was performed at study registration to evaluate the prevalence of vulnerabilities and their impact on overall survival (OS) and 30-day induction mortality rates (IM) in this cohort selected for fitness to receive IC. Methods E2906 study design and results have been presented previously [n=727, age ≥60 years, randomized 1:1 to ‘standard 7&3‘ & high dose cytarabine (Arm A) vs. single agent clofarabine (CLO, Arm B), as remission induction (Step 1) and consolidation (Step 2)]. There was no difference in composite complete remission (CCR, 50%) or IM (8.5%), and CLO was inferior for OS. A baseline GA was a key secondary protocol objective, offered to all patients, and n=532 (73%) participated. We assessed Geriatric Depression Scale (GDS, none vs. any depressive symptoms, n=524); cognitive screen using Mini-Mental Exam Section (MMES, score 8/8 vs. <8, n=516); ADL & Instrumental ADL (iADL), (need for assistances vs. not n=526); a Medical Outcomes Study SS Survey (MOS-SS, measured as per unit increase, n=527); a Comorbidity survey ( ≤4 vs. ≥5 patient-reported comorbidities, n=530), patient-reported prescription medications use (PM, 0-3 vs. ≥4, n=519); and a survey of Sexual Desire (n=491) and Sexual Activity (n=477) within 4 weeks of AML diagnosis. Association of GA domains with OS, IM, and achievement of CCR was evaluated using the Chi-squared, Fisher's exact, and Wilcoxon rank sum test. Survival analysis was performed using the Cox proportional hazards models, adjusted for treatment arm. All p-values are 2-sided. Results The median age among those participating in GA battery was 67 yrs (range 60-85), including 38% age ≥70. There were 42% females, and ECOG performance status was 0 (28%), 1 (54%), 2 (16%), or 3 (2%). Central Cytogenetic review was classified (ELN2017) as Favorable (3%), Intermediate (66%), and Adverse (31%) risk. There was a notable rate of GA scores outside ‘normal’ clinical cutoff, including Depression (GDS 31%), cognitive and functional impairment [MMSE (37%), ADL (25%) and iADL (32%)], ≥5 Comorbidities (23%), and ≥4 PM's (44%). 81% & 76%, respectively, reported no sexual activity and low/none sexual desire. MOS-SS tended to be high in this cohort [mean (SD) score 87 (17)]. We observed a significant association of GA domains with OS & IM. For OS, absence of depressive symptoms [GDS, Hazard Ratio (HR) 0.79, 95% confidence Intervals (CI) 0.64-0.97, p=0.025)], MMES 8/8 (HR 0.78, 95%CI 0.64-0.96, p=0.016), requiring no assistance with ADLs (HR 0.65, 95%CI 0.52-0.82, p<0.001) and iADLs (HR 0.69, 95%CI 0.57-0.85, p<0.001), and ≤4 Comorbidities (HR 0.68, 95%CI 0.54-0.84, p=0.001) were significant for superior OS; use of ≥4 PM's was associated with inferior OS (HR 1.32, 95%CI 1.09-1.61, p=0.005). There was no association of sexual activity/desire, BMI ≥30 kg/m2, or MOS-SS with OS. IM was significantly higher among those with any depression symptoms (GDS, p=0.005), any ADL (p=0.010) or iADL (p=0.013) impairment, ≥5 comorbidities (p=0.037) and ≥4 PM's (p=0.001); there was no association with MOS-SS or MMES. There was no significant association of GA scores with cytogenetic risk group or with CCR rates. Only ADL independence (p=0.048), and possibly Comorbidity ≤4 (p=0.071), were associated with proceeding to Step 2. Conclusions In this large prospective cohort of fit older adults with AML selected to receive IC, we observed high rates of PRO-assessed GA vulnerability, which was significantly associated with inferior OS and higher IM rates, and (for ADL impairment) lower rates of proceeding to consolidation therapy. This suggests that functional and cognitive impairments are prevalent and can significantly impact outcome even in fit older adults. Despite potential long-term OS advantages of IC previously observed in E2906, efforts to systematically recognize those at higher risk based on GA PROs are needed to help identify patients who may be more appropriate for study of lower intensity treatment options to mitigate impact on IM and OS. SImilarly we plan to evaluate the potential benefit of GA-driven supportive care to improve patients' outcomes.

Abstract The incidence of venous thromboembolism (VTE) in patients with acute lymphoblastic leukemia (ALL) receiving asparaginase-based induction is high despite primary thromboprophylaxis. Our aim was to derive and externally validate a VTE risk prediction model in patients with ALL receiving asparaginase-based induction. We conducted a multicenter retrospective cohort study of patients (aged ≥18 years) with newly diagnosed ALL receiving asparaginase-based induction. The derivation and external validation cohorts included 306 and 94 patients, respectively. Primary outcome was VTE at any site. A cause-specific Cox proportional hazards model stratified by thromboprophylaxis and center was performed to identify VTE risk factors in the derivation cohort. A risk prediction model for VTE at 30 days was derived using variables with P value < .05 in the multivariable model and was tested in the validation cohort. VTE risk factors on multivariable analysis in the derivation cohort included D-dimer ≥1 μg fibrinogen equivalent unit per mL (hazard ratio [HR], 2.64; 95% confidence interval [CI], 1.07-6.5) and hemoglobin (HR for each 1 g/dL increment, 1.19; 95% CI, 1.06-1.34) at ALL diagnosis. A VTE risk score based on these variables distinguished between a 4% (95% CI, 0.72-12) and 20% (95% CI, 14-27) 30-day cumulative incidence of VTE in the derivation cohort, with similar findings in the validation cohort (area under the curve, 0.56). The negative predictive value for VTE at 30 days was 96% and 93% in the derivation and validation cohorts, respectively, and the positive predictive value was 20% in both. We derived and validated a model using D-dimer and hemoglobin, which stratifies VTE risk in patients with ALL receiving asparaginase-based induction.

Introduction: Brexucabtagene autoleucel (brexu cel) is a CD19-targeted chimeric antigen receptor (CAR) T cell therapy approved for the treatment of adults with relapsed/refractory (R/R) acute lymphoblastic leukemia (ALL). Some patients (pts) proceed with a consolidative allogeneic hematopoietic cell transplant (HCT) after breux cel. We do not know which pts can safely avoid a consolidative HCT and its associated morbidity. Methods: We conducted a retrospective cohort study utilizing the Real-World Outcomes Collaborative of CAR-T in Adult ALL (ROCCA) dataset. ROCCA is a registry of brexu cel pts in 32 centers in North America. We defined complete remission (CR) as < 5% blasts in the bone marrow and no central nervous system (CNS) or extramedullary (EM) disease on or around D28 after brexu cel. We defined measurable residual disease negative (MRD-) CR as CR and no abnormal blasts in the bone marrow by multiparameter flow cytometry, quantitative polymerase chain reaction, ClonoSeq next generation sequencing (NGS), or other sequencing modalities with lower sensitivity. ClonoSeq NGS has a sensitivity of 10-6, while the other modalities have a sensitivity of at least 10-4. We defined progression free survival (PFS) as the time from CAR-T infusion to relapse or death, censored at the date of last follow-up. Statistical analyses were performed in R. Univariable Cox proportional hazards regression analyses were performed to determine the association of pre-specified variables with PFS. Variables known to be associated with CAR T outcomes in ALL were entered into a multivariable model. HCT was incorporated as a time-varying covariate. Results: During the study period, 281 pts were infused with brexu cel. We focused our analysis on 172 (61%) pts with confirmed MRD- CR on D28, as that is the group with clinical equipoise regarding maintenance strategy. 38 (22%) of those pts received a consolidative HCT, 30 (17%) received another form of maintenance therapy (primarily tyrosine kinase inhibitors for Philadelphia (Ph)-chromosome positive ALL), and 104 (60%) pts received no maintenance therapy. Pts who underwent consolidative HCT were younger (median age 35 years) than those who received no maintenance (42y) (p = 0.023) and were less likely to have a history of prior HCT (13% vs. 47%, p < 0.001). No differences were observed with respect to sex, TP53 mutation status, prior inotuzumab (ino) or blinatumomab (blina) exposure, disease burden prior to CAR, or development of any cytokine release syndrome (CRS) or any neurotoxicity with brexu cel. We performed univariable Cox proportional hazard regression analyses among pts in MRD- CR on D28, excluding those who received other maintenance therapy besides HCT; the median follow up was 8.1 months. In univariable analyses, D28 MRD negativity by ClonoSeq NGS (versus MRD negativity by other, less sensitive methods), development of CRS, and pre-CAR BM blasts < 5% were associated with improved PFS; prior ino exposure was negatively associated with PFS (p < 0.05). Age, sex, Ph status, TP53 status, and neurotoxicity development were not associated with PFS. In a multivariable model incorporating ALL type, prior HCT, prior ino/blina, and pre-CAR blast burden, as well as consolidative HCT as a time-varying covariate, only MRD negativity by ClonoSeq NGS with at least 10-6 sensitivity retained statistical significance (PFS hazard ratio 0.34, 95% confidence interval (CI) 0.15-0.77, p = 0.005). Pts who were MRD- by ClonoSeq NGS on D28 and received no maintenance had favorable 6m PFS of 76% (95% CI: 59-98%) and OS of 100% with a median follow up of 6.3 months in this subgroup. Among those in MRD- CR by NGS, HCT as a time-varying covariate was not associated with improved PFS (HR 0.6, p = 0.6). Conclusions: In a large real-world cohort of adults with R/R B-ALL infused with brexu cel, we identified practice variation regarding the use of consolidative HCT. Among brexu cel recipients who entered an MRD- CR, we identified ClonoSeq NGS MRD negativity as a novel predictive factor of favorable oncologic outcomes, even without a consolidative HCT. Similar results have been obtained in pediatric ALL patietns ftreated with 41BB-based tisagenleucleucel (Pulsipher et al., Blood Cancer Discovery 2022). Longer follow-up is needed to validate the safety of omitting consolidative HCT in such pts, but these results encourage the potential for definitive therapy with brexu cel when D28 ClonoSeq NGS MRD is negative.

Introduction: Brexucabtagene Autoleucel (brexu-cel) is the first CD19-targeting chimeric antigen receptor (CD19.CAR) T-cell therapy approved for the treatment of relapsed/refractory (r/r) B-cell acute lymphoblastic leukemia (B-ALL) in adult (≥18 yo) patients (pts) based on results from the ZUMA-3 trial. However, data on the safety and efficacy of CAR-T cells in older pts (≥60 yo) remains limited, with only 8 pts >65 yo enrolled in the ZUMA-3 trial. We evaluated the treatment characteristics and outcomes with use of brexu-cel amongst patients ≥60 yo in the Real-World Outcomes Collaborative for CAR-T in ALL (ROCCA) consortium database. Methodology: ROCCA is a consortium of over 30 U.S.-based institutions with a database of adult pts with B-ALL who received brexu-cel as standard of care therapy. We identified pts ≥60 yo and further stratified them into two cohorts: 60-69 yo and ≥70 yo. Outcomes of interest included OS, PFS, ORR, and toxicities (CRS and ICANS). Both OS and PFS were calculated from the day of brexu-cel infusion. Response assessment occurred on day +28, and MRD evaluation was per institutional practices. CRS and ICANS were graded according to the American Society for Transplantation and Cellular Therapy criteria. Results: Of 280 brexu-cel recipients in the ROCCA database, 73 (26%) were ≥60 yo, of which 58 (79%) were between 60-69 yo and 15 (21%) were ≥70 yo. Among pts ≥60 yo, the median age at infusion was 65 (range 60-81). Pts were heavily pretreated with a median of 3 prior lines of therapy (range 2-9). Prior therapies included: allogeneic HSCT (38%), inotuzumab ozogamicin (41%), and blinatumomab (62%). Forty pts (55%) had Ph-negative B-ALL, 24 (33%) had Ph+ B-ALL and 9 (12%) had Ph-like B-ALL. When grouped by HCT-CI equal to 0, 1-2 or ≥3, a higher proportion of pts ≥60 yo had HCT-CI ≥3 (19% vs. 7% in <60 yo; p=0.004). Pre-apheresis, 33 pts (45%) had active disease (>5% marrow blasts or extramedullary disease), 34 (47%) were in CR (of whom 14 were MRD-negative) and 6 had unknown disease status. Following brexu-cel, 43 (59%) achieved MRD-negative CR, 20 (27%) had MRD + or CR with unknown MRD status, 6 (8%) had refractory disease and 5 had no disease evaluation available. The ORR was similar between pts 60-69 and ≥70 yo (MRD-negative CR rate: 58% vs 61%, r/r to brexu-cel: 9% vs 6%) and was comparable to pts <60 yo (MRD-negative CR 66%; r/r disease of 9%). The rate of all grade ICANS was higher in pts ≥70 (77%) than in pts 60-69 (47%) or pts <60 (49%), with grade 1-2 ICANS occurring at a significantly higher rate in pts ≥70 (44% vs. 20% in 60-69 and 20% in <60, p=0.049). Grade 3-4 ICANS were similar between the groups: 33%, 27% and 29% in the ≥70, 60-69, and <60 groups, respectively. Conversely, rates of CRS were similar across age groups (80-84%). There was no statistically significant difference in the rate of grade 3-4 CRS which was 17% in pts ≥70, 4% in pts 60-69, and 11% in pts <60 yo. With a median follow-up of 332 days (range 8-936 days) from infusion, pts ≥60 yo had a median PFS of 395 days compared to 547 days in pts <60 yo. Median PFS was lower in the ³70 yo (231 days) compared to 677 in the 60-69 yo cohort. No statistically significant difference was found between the <60 and ≥60groups in 6- and 12-month PFS rates (6 months PFS: 66% vs 64%, p=0.77 and 12 months PFS: 57% vs 57%, p=1.00). When pts ≥60 yo were stratified by age, pts ≥70 yo had similar 6-month PFS compared to other age groups but significantly lower 12-month PFS (38%; vs. 64% in pts 60-69and 57% in pts <60, p=0.001). Median OS was not reached in any of the age groups, and there was no statistically significant difference in 6-month OS (72% in ≥ 70 vs. 82% in the 60-69 vs. 82% in <60, p=0.14) or 12-months OS (61% in ≥ 70 vs. 69% in 60-69 vs. 73% in <60, p=0.18). Conclusion: This is the largest study to date of older B-ALL pts receiving CAR-T cells. We observed that older pts, particularly those aged 60-69, have similar outcomes to younger pts. However, pts ≥70 yo had lower median and 12-month PFS when compared to younger patients. Additionally, pts ≥70 yo had higher rates of grades 1-2 ICANS. An important limitation of this analysis is the potential selection bias among clinicians when selecting older patients for this treatment. Longer follow-up, including inclusion of additional pts ≥70 yo is needed to confirm these results, and further studies are needed to identify the optimal approach for use of CAR T-cell therapy in patients in this age group.

Background: Patients with acute lymphoblastic leukemia (ALL) receiving L-asparaginase (ASP) based induction therapy have a high risk of venous thromboembolism (VTE). Studies investigating universal thromboprophylaxis strategies have yielded sub-optimal results. Risk prediction models are needed to identify high-risk patients who would be candidates for intensification of thromboprophylaxis, and lower risk patients who are unlikely to benefit. Aims: Derive and externally validate a risk prediction model for VTE in patients with ALL receiving ASP therapy. Methods: We conducted a multicenter, international, cohort study of patients with newly-diagnosed ALL receiving ASP-based induction therapy (≥18yrs). The derivation and external validation cohorts included 306 and 97 patients without VTE prior to ASP therapy, respectively. Patients on therapeutic anticoagulation at index were excluded. Patients were followed from date of first ASP dose for 100 days post ALL diagnosis or until VTE, therapeutic anticoagulation or death. Candidate predictors were documented at ALL diagnosis and included demographics, disease and treatment characteristics, VTE history, comorbidities, thromboprophylaxis, complete blood count, fibrinogen and d-dimer. D-dimer was only analyzed within the 7 derivation cohort centers who routinely tested this at ALL diagnosis with <20% missing values. Primary outcome was VTE at any site (centrally confirmed). Secondary outcomes included major bleeding by ISTH criteria. Cause-specific Cox proportional hazard regression was performed to identify VTE risk factors in the derivation cohort while treating death as a competing event. Variables with p-value <0.1 on univariable analysis were included in a multivariable model and subsequently used in the risk model if p-value <0.05. Lastly, the derived VTE risk prediction model was tested in the external validation cohort for association with time to VTE using cause-specific Cox proportional hazard model. All analyses were stratified by center and use of low molecular weight heparin prophylaxis (at any dose on the date of first ASP dose). Results: The cumulative incidence of VTE in the derivation cohort was 17% at 30 days (95% confidence interval [CI] 13% - 21%) and 22% at 90 days (95% CI 17% - 27%). The multivariable model included hyperlipidemia (hazard ratio [HR] 1.35; 95% CI 0.56 - 3.27), body mass index ≥ 25 kg/m² (HR 1.49; 95% CI 0.75 - 2.95), platelet count ≥ 25 x 10⁹/L (HR 1.42; 95% CI 0.67 - 3.00), increasing hemoglobin per 1 g/dL (HR 1.17; 95% CI 1.03 - 1.32) and d-dimer ≥ 1 µg FEU/mL (HR 2.68; 95% CI 1.08 - 6.66). Hemoglobin as a continuous variable and d-dimer ≥ 1 µg FEU/mL were included in the final model and used to create a risk score which was weighted by estimated log-HR sum of these risk factors. The lowest risk quartile (risk score below 2.1) successfully differentiated between a lower 30-day cumulative VTE incidence (4%, 95% CI 0.72% - 12%) compared with the other quartiles (20%, 95% CI 14% - 27%; HR 4.40, 95% CI 1.54 - 12.5) which were defined as high risk (score ≥2.1). The risk score's negative predictive value (NPV) for VTE at 30 days was 96% and positive predictive value (PPV) was 20%. The validation cohort (n=97 from 3 external cohorts with routine d-dimer measurement) included 16 (16.5%) patients in the low-risk group and 81 (83.5%) in the high-risk group, with a 30-day VTE incidence of 6.3% (95% CI 0% - 17%) and 21% (95% CI 12% - 30%), respectively (HR 6.22; 95% CI 0.85 - 45.8; p = 0.073)). The NPV (93.7%) and PPV (21%) were comparable to the derivation cohort. The 30-day incidence of major bleeding was 0% (95% CI NR - NR) in low-risk patients (HR 1.36; 95% CI 0.27 - 6.77) and 2.0% (95% CI 0.55% - 5.4%) in the high-risk group. Conclusion: Patients with ALL receiving ASP induction therapy have a 17% VTE risk at 30 days. We derived and externally validated a VTE risk prediction model based upon d-dimer and hemoglobin. This model successfully identifies at least 16.5% of patients with ALL who have a low VTE risk after ASP treatment. Using this model, novel prevention strategies which may be associated with cost and risk could now be tailored to patients with higher risk. Prospective studies are needed to validate the model's performance and role in VTE risk management.

Background: The addition of midostaurin (M), an oral multi-kinase inhibitor, to intensive chemotherapy (IC) prolongs survival in newly diagnosed (ND) FLT3 mutated (m) AML. It is not known if there is a benefit to more potent and selective FLT3 inhibitors. Among these is Gilteritinib (G), now approved as a single agent in relapsed/refractory FLT3m AML. Combined with IC, G also leads to high measurable residual disease (MRD)negative (-) composite complete remission (CRc) in FLT3 Internal Tandem Duplication (ITD)m AML. The aim of the PrECOG 0905 study was to compare FLT3m clearance and CRc rates of G vs M with IC in adults with ND FLT3m AML. Methods: We conducted a randomized, open-label, phase 2 trial comparing G to M in combination with IC during induction and consolidation in ND AML pts with centrally PCR detected FLT3 ITD or TKD mutations. Pts age 18-70 with non M3 AML and no known core binding factor rearrangement were eligible. Pts were stratified by mutation type (TKD only vs. ITD (+/- TKD)), NPM1 mutation status, and FLT3-ITD allelic ratio. Induction consisted of cytarabine 100 mg/m2 by continuous infusion daily, on day (d) 1-7 and daunorubicin 90 mg/m2 IV on d 1-3. G 120 mg daily or M 50 mg twice daily was given orally on d8-21. Consolidation (up to 4 cycles) began within 60 d of induction with Cytarabine (1.5-3 g/m2 IV) X 6 doses and G or M (as per randomization) on d8-21. Pts could proceed to transplant (HCT) at any time. Maintenance was not included. The primary outcome was FLT3m MRD (-) CRc after induction. MRD for TKD mutations was tested by PCR (sensitivity 10-2); ITD MRD was tested by amplicon-based NGS (sensitivity 10-4). Safety and efficacy were analyzed in all eligible pts who received treatment. Secondary endpoints included comparison of CRc, MRD by flow cytometry (sensitivity 10-3), and survival. Results: From 11/2019 to 11/2022, 722 pts were screened at 37 centers, 180 pts randomized, and 177 pts (58% female, 77% white, 8.5% black, 8.5% hispanic) treated on the G (n=90) or M (n=87) arm. Median age was 54, with 27.7% > age 60. FLT3-ITD was present in 80% in the G arm and 78.2% in the M arm. Of those with FLT3-ITD, NPM1 was detected in 56.9% pts in G arm and 58.8% in M arm. 24.4% G and 20.7% M pts had co-occuring FLT3-ITD, NPM1 and DNMT3A mutations. Adverse karyotype was seen in 3.4% G and 9.3% M while 10% G and 13.8% M were ELN 2022 adverse risk. For pts on G arm, 85.6% achieved CRc compared to 72.4% for M (p=0.042). 5 (5.6%) pts on G arm and 6 (6.9%) on M arm received 2 cycles in induction. Post induction, the FLT3m- CRc rate was 40% for G vs 47.1% for M (p=0.366). FLT3-TKD only mutated pts achieved CRc in 88.9 % with G and 63.2% with M and FLT3m- CRc in 72.2% and 63.2% respectively. FLT3-ITDm (+/- TKDm) pts achieved CRc/FLT3m- CRc in 84.7%/31.9% with G and 75%/42.6% with M, respectively. In pts with FLT3-ITD, NPM1 and DNMT3A mutations, 95.5% G and 72.2% M achieved CRc and 50% G vs 33.3% on M achieved FLT3m- CRc. Flow cytometry MRD negative CRc was documented in 64.4% on G arm and 59.8% on M arm after induction (p=0.539). On G arm 67 (74%) patients received at least one cycle of consolidation compared to 53 (61%) pts on M arm. On exploratory analysis, 54 (66%) G and 40 (46%) M were reported to proceed to HCT in first remission. FLT3m testing was done post consolidation cycle 1 in 27 pts in FLT3m+ CRc after induction and 15/18 (83%) on G and 4/9 (44.4%) on M converted to FLT3m-. On multivariate logistic regression analysis for FLT3m-CRc post-induction, FLT3-ITD allelic ratio, NPM1m, WBC and hemoglobin at baseline were significant at the 0.10 two-sided level, while treatment arm, and 2017 ELN risk were not. There were no deaths from treatment-related (TR) adverse events (TRAEs) while grade >=3 TRAE was reported in 73%G vs 70% M during induction and 79%G vs 73%M pts during consolidation. Conclusion: Induction therapy with daunorubicin 90 mg/m2 X 3 days, cytarabine 100 mg/m2 and gilteritinib results in an excellent CRc rate with no TR deaths in pts with ND FLT3m AML up to age 70. Compared to M, G increased the CRc but not the FLT3m- CRc rate after induction. More post induction FLT3m+CRc pts who received G became FLT3m- after consolidation cycle 1 and more G pts succeeded in proceeding to HCT. Future survival data will help evaluate the clinical impact of G and MRD assessments in ND FLT3mAML. Larger studies will be needed to establish most predictive timing of MRD and for definitive comparisons of these drugs in patients with specific mutation profiles ( ie TKD, ITD/NPM1/DNMT3).