Citations

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: Despite the promising efficacy of CAR-T for patients with relapsed or refractory (R/R) large B-cell lymphomas (LBCL), more than 60% of patients will relapse, the majority of which occur in the first 6 months. Approximately 30% of patients with LBCL treated with CAR-T achieve a partial response (PR) on day 30 (D30) PET-CT assessment. Of patients in a D30 PR, 70% will eventually progress, yet the standard of care remains close observation. Early consolidative treatment strategies utilizing therapies with a different mechanism of action may improve outcomes, but there are currently no reliable biomarkers. Epcoritamab (Epco), a bispecific antibody directed against CD20 and CD3, has been approved by the FDA for LBCL patients who relapse after at least 2 lines of therapy. By treating prior to overt relapse, Epco has the potential to salvage inadequate responses post CAR-T. This study is a trial-in-progress that will evaluate the efficacy of epco compared to observation for patients with LBCLs achieving a PR on D30 post CAR-T PET-CT assessment. Methods This is an investigator-initiated, randomized, phase II, multicenter, open-label study (NCT06238648) evaluating epco monotherapy for a fixed duration of 12 cycles compared to observation for LBCL patients with D30 PR after standard of care CAR-T. A maximum of 120 patients will be randomized 1:1 to epco or observation across 10 academic centers. Stratification factors include line of CAR-T (second vs third line) and costimulatory domain (CD28 vs 4-1BB). Key inclusion criteria include PET evidence of a D30 PR. non-bulky disease ( <7.5cm), ANC of >1000, hemoglobin >7 g/dL if asymptomatic or >8 if symptomatic, platelet count >50,000. G-CSF, pRBCs and platelet transfusions are allowed. Key exclusion criteria include ongoing or uncontrolled CRS or ICANS, and active or symptomatic CNS disease. This study is available to all eligible patients, regardless of race, gender, or ethnic origin. To adapt to current practices, prior bispecific antibody exposure is allowed if used as holding or bridging therapy without disease progression. Epco is administered subcutaneously at a dose of 0.16mg on day 1, 0.8mg on day 8, prior to full dose of 48mg on day 15. Epco is administered weekly in 28 day cycles (C) for C1-3, on day 1 and 15 of C4-9 and on day 1 of C10-12. PET-CT response is assessed by the 2014 Lugano criteria after 2 cycles, and then every 3 months during active treatment. The primary objective is efficacy, measured as conversion from D30 PR to CR. The secondary endpoints include frequency and severity of treatment emergent adverse events, ORR, duration of response, duration of complete response, progression free survival, event free survival, and overall survival. Peripheral blood samples will be collected pre-treatment and during treatment to assess for biomarkers of response and resistance and CAR-T persistence. The study was activated in January 2024 and recruitment is ongoing.

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.

Abstract Introduction: Brexu-cel is a highly effective treatment for R/R B-ALL, with complete responses achieved in 71% of patients (pts) treated in the pivotal ZUMA-3 trial. Patients with B-ALL with high-risk (HR) genetics are known to have inferior outcomes with chemotherapy, but little is known about the influence of HR ALL genetics on responses to chimeric antigen receptor (CAR)-T in adults. In this study, we assessed the impact of HR ALL genetics on outcomes in a large cohort of adult patients treated with brexu-cel for R/R Philadelphia chromosome (Ph)-negative B-ALL. Methods: Patient characteristics and outcomes were obtained from the Real-World Outcomes Collaborative of CAR-T in Adult ALL (ROCCA) database which includes data from 40 U.S. centers. NCCN guidelines (NCCN Guidelines in Oncology, ALL v2.2025) were used to define HR B-ALL genetics; lack of HR genetics was defined as standard-risk (SR). The primary outcome was event-free survival (EFS), defined as lack of response, disease progression, or death from any cause. Secondary outcomes were overall survival (OS), relapse free survival (RFS) and response rates including complete response (CR), CR incomplete count recovery (CRi), measurable residual disease negative CR (MRD-) by flow or NGS and progressive disease (PD). Multivariable models were adjusted for age, pre-infusion blast percentage, prior allo-HCT, and post CAR-T allo-HCT (modeled as a time-varying covariate). Results: The cohort included 286 pts: 169 with HR and 117 with SR B-ALL. The HR cohort included TP53m (n=24, 14%), KMT2Ar (n=16, 9%), CRLF2r (n=65, 39%) and other HR genetics such as JAK2 and other Ph-like, IKZF1, complex cytogenetics (n=64, 38%). Relative to SR pts, HR pts were more commonly Hispanic (50% vs 28%). HR and SR pts had similar disease burden pre-apheresis (>5% blasts: 58% vs 53%), prior blinatumomab (60% vs 58%), prior inotuzumab (42% vs 46%), and prior allo HCT (27% vs 37%). The presence of CNS disease (11% HR vs 12% SR) and extramedullary disease (EMD, 22% HR vs 29% SR) at apheresis was also similar. CR/CRi was achieved in 90.5% of evaluable HR pts (n=147) and 90.2% of evaluable SR pts (n=102); MRD- rates were also similar between HR and SR pts at 78.9% and 78.2% respectively. In unadjusted analyses, EFS did not significantly differ between HR pts (median 9.6 mos; 1-yr: 46%, 95% CI 38%-54%) and SR pts (median 11.6 mos; 1-yr: 48%, 95% CI 38%- 58%). Median RFS (HR: 12.2 mos, SR: 13.3 mos) and median OS (HR: 22.4 mos, SR: 21.0 mos) were also similar. Multivariable models demonstrated no significant associations between HR B-ALL and EFS (HR 1.09, 95% CI 0.73-1.63), RFS (HR 1.13, 95% CI 0.71-1.80), or OS (HR 0.96, 95% CI 0.62- 1.48) relative to SR ALL. 28% of HR patients and 21% of SR patients underwent consolidative allo-HCT. Among the HR subgroup, CR/CRi rate was lowest in KMT2Ar (71%) relative to TP53m (95%), CRLF2r (95%), and other HR genetics (89%). The median EFS was lowest in KMT2Ar (4.1 mos), followed by TP53m (6.9 mos), CRLF2r (11.6 mos), and other HR (11.1 mos). Median OS was also lowest in KMT2Ar (6.8 mos) vs 22.4 mos in TP53m and not reached in CRLF2r or other HR. PD was highest in KMT2Ar pts (29%), as compared to 11% HR other, 10% SR, and 5% TP53 and CRLF2r. The rate of relapse among those that achieved CR across the groups was similar and ranged between 28% -40%. Rates of CD19 negative relapse were similar between all subgroups (13%-15%), however 21% of KMT2A pts underwent myeloid transformation as compared 0% for TP53 and CRLF2 pts, and 2% among other HR and SR pts. 25% of KMT2Ar patients underwent consolidative allo-HCT as compared to 32% CRLF2 pts, 29% TP53 pts, 25% other HR pts and 21% SR pts. Multivariable models evaluating the different genomic subgroups demonstrated that relative to SR B-ALL, only KMT2Ar was associated with inferior OS (HR 3.17, 95% CI 1.53-6.58, p=0020). No associations were seen between HR subgroups and EFS. Conclusion: To our knowledge, this analysis represents the largest examination of adult B-ALL recipients of CAR-T assessed by genomic risk group. We found that response rates and survival outcomes following brexu-cel were similar among HR and SR B-ALL pts, including pts with TP53m and CRLF2r. However, pts with KMT2Ar had lower response rates and dismal EFS and OS, with higher rates of PD and myeloid transformation at relapse, suggesting that alternative strategies are necessary to improve outcomes for patients with R/R KMT2Ar B-ALL.

PURPOSE Off-the-shelf, allogeneic CD19 chimeric antigen receptor (CAR) T-cell products may improve access to treatment versus autologous ones. We report the phase I experience of the allogeneic CD19 CAR T-cell product cemacabtagene ansegedleucel (cema-cel) and its predecessor, ALLO-501, in CD19 CAR T-naïve patients with relapsed/refractory large B-cell lymphoma (R/R LBCL). METHODS In the ALPHA2/ALPHA studies, the safety and efficacy of allogeneic CD19 CAR T cells were evaluated in CD19 CAR T treatment-naïve patients with R/R LBCL. Patients received healthy donor-derived, human leukocyte antigen–unmatched cema-cel/ALLO-501 following a 3-day lymphodepletion regimen of fludarabine (30 mg/m 2 once daily), cyclophosphamide (300 or 500 mg/m 2 once daily), and escalating doses of the anti-CD52 monoclonal antibody, ALLO-647. RESULTS As of September 26, 2024, 33 CD19 CAR T-naïve patients with LBCL (median age, 66 years; median number of previous therapies, 3) received allogeneic CAR T cells. CAR T-cell expansion was observed following infusion, with persistence observed up to 4 months. The overall and complete response (CR) rates were 58% and 42%, respectively; the median duration of response in patients with a CR was 23.1 months. The most common treatment-emergent adverse events were hematologic toxicities. No cases of graft-versus-host disease, immune effector cell–associated neurotoxicity syndrome, or grade ≥3 cytokine release syndrome were reported. CONCLUSION Allogeneic CD19 CAR T cells demonstrated promising overall and durable CR rates with a manageable safety profile in CD19 CAR T-naïve patients with R/R LBCL, supporting additional evaluation of cema-cel in patients with LBCL.

ZUMA-12 is a multicenter phase 2 study evaluating axicabtagene ciloleucel (axi-cel) autologous anti-CD19 chimeric antigen receptor (CAR) T-cell therapy as part of first-line treatment for high-risk large B-cell lymphoma (LBCL). In the primary efficacy analysis (n = 37; median follow-up, 15.9 months), axi-cel demonstrated a high rate of complete responses (CR; 78%) and a safety profile consistent with prior experience. Here, we assessed updated outcomes from ZUMA-12 in 40 treated patients after ≥3 years of follow-up. Eligible adults underwent leukapheresis, lymphodepleting chemotherapy, and axi-cel infusion (2 × 106 CAR T cells/kg). Investigator-assessed CR, objective response, survival, safety, and CAR T-cell expansion were assessed. The CR rate among response-evaluable patients (n = 37) increased after the primary analysis to 86% (95% confidence interval [CI], 71%-95%), with a 92% objective response rate. After a median follow-up of 47.0 months (range, 37.1-57.8 months), 36-month estimates (95% CI) of duration of response and event-free, progression-free, and overall survival were 81.8% (63.9%-91.4%), 73.0% (55.6%-84.4%), 75.1% (57.5%-86.2%), and 81.1% (64.4%-90.5%), respectively. In total, 4 patients had new malignancies, 2 occurring after the data cutoff of the primary analysis; none were axi-cel–related. Eight patients died on study, 2 of whom died from nonrelapse mortality causes. After long-term follow-up, axi-cel demonstrated a high durable response rate, with no new safety signals after the primary analysis, suggestive of an effective first-line therapy with curative intent in high-risk LBCL. Further assessments are needed to determine its benefit vs standard of care. This trial was registered at clinicaltrials.gov, as NCT03761056.

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.