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Brexucabtagene-autoleucel (brexu-cel) produces high rates of measurable residual disease-negative (MRD-) complete response (CR) in adults with Philadelphia-chromosome positive (Ph+) acute lymphoblastic leukemia (ALL); however, subsequent relapses remain frequent. It is unclear whether maintenance with tyrosine kinase inhibitors (TKIs) can enhance remission durability. We evaluated outcomes among adults with relapsed/refractory Ph+ ALL who received commercial brexu-cel and achieved MRD- CR across 19 U.S. institutions. Considering TKI maintenance as a time-varying covariate, we analyzed outcomes based on receipt of subsequent TKI maintenance versus no maintenance. Patients receiving consolidative transplantation or non-TKI maintenance were excluded. Fifty-one patients were included: 20 received TKI maintenance and 31 received no maintenance. The use of TKI maintenance was associated with a significantly lower 1-year cumulative incidence of relapse (HR 0.12; 95% CI, 0.02-0.88; p=0.037) which translated into improved progression-free survival (PFS, HR 0.19; 95% CI, 0.04-0.85; p=0.029) and a trend towards improved overall survival (OS, HR 0.34; 95% CI, 0.07-1.62; p=0.18). There was no difference in non-relapse mortality (NRM, HR 0.83; 95% CI, 0.12-5.87; p=0.85). This real-world analysis supports the administration of TKI maintenance in Ph+ ALL following achievement of MRD- CR with brexu-cel as a strategy to improve PFS following chimeric antigen receptor T cell therapy.

This multicenter, single-arm, phase 1/2 study evaluated the safety and efficacy of CD19-directed allogeneic chimeric-antigen-receptor (CAR) immunotherapy CTX110 in adult patients with relapsed/refractory (r/r) B-cell non-Hodgkin lymphoma (NHL). Patients received 1 or 2 treatment courses: standard lymphodepletion, followed by 1 CTX110 infusion at dose levels (DLs) 1-4 (3-60 × 107 CAR T-cells; dose escalation, N=32), or 2 infusions at DL4 on days 1 and 35 (cohort expansion, N=31). Primary endpoints in dose escalation and cohort expansion were incidence of dose-limiting toxicities and objective response rate, respectively. CTX110 was administered to 63 heavily pretreated patients: 59% primary refractory, 43% with ≥3 prior treatment lines. Among 57 patients whose first infusion was DL≥3, rates of objective and complete response (CR) were 65% and 39%, respectively. Among 22 patients achieving CR, 5 (23%) had ongoing CR at data cutoff, with 15-50 (median 34) months follow-up. The 2-infusion regimen appeared to prolong response duration compared to 1 infusion (hazard ratio 0.65). Cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) were reported in 54% and 13% of treated patients, respectively, including 2 grade ≥3 cases each. The most common grade ≥3 adverse events were neutropenia (59%), and anemia and thrombocytopenia (35% each). Serious adverse events occurred in 32% of treated patients, including CRS (14%), ICANS (8%), and febrile neutropenia (6%). In this r/r NHL population, CTX110 was well-tolerated, resulting in clinically meaningful responses at DL≥3, with a second infusion demonstrating evidence of further clinical benefit. This trial (NCT04035434) was registered at www.clinicaltrials.gov.

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 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.

Importance Treatment for cognitive dysfunction due to postacute sequelae of long COVID (ie, symptoms of fatigue, malaise, weakness, confusion that persist beyond 12 weeks after an initial COVID infection) remains a significant unmet need. Objective To test evidence-based rehabilitation strategies for improving cognitive symptoms in persons with long COVID. Design, Setting, and Participants This was a 5-arm, multicenter, randomized clinical trial of 3 remotely delivered interventions conducted between August 17, 2023, and June 10, 2024. The study took place at 22 trial sites and included the screening of individuals with cognitive long COVID. Interventions Participants were randomized to 1 of 5 arms: adaptive computerized cognitive training (BrainHQ [Posit Science]), cognitive-behavioral rehabilitation involving both group and individual counseling sessions (PASC-Cognitive Recovery [PASC-CoRE]) paired with BrainHQ, and transcranial direct current stimulation (tDCS) paired with BrainHQ. Two comparator arms were included as follows: unstructured computer puzzles and games (active comparator) and sham tDCS paired with BrainHQ. The interventions occurred 5 times per week over 10 weeks. Main Outcomes and Measures Cognitive and behavioral in-person assessments were performed at baseline, midintervention, at the end of intervention, and 3 months after the end of the intervention. The primary outcome measure was the modified Everyday Cognition Scale 2 (ECog2) completed at the end of the intervention compared to the baseline visit based on participant self-report looking back over the prior 7 days. Results A total of 378 individuals were screened, from which there were 328 participants (median [IQR] age, 48.0 [37.0-58.0] years; 241 female [73.5%]; race: 15 Asian [4.6%], 47 Black [14.3%], and 235 White [71.6%]; ethnicity: 52 Hispanic [15.9%]). None of the 3 active interventions demonstrated benefits on the modified ECog2 in the intention-to-treat population by the end of the intervention period. The adjusted differences in mean change were 0.0 (95% CI, −0.2 to 0.2) for BrainHQ vs active comparator, 0.1 (95% CI, −0.1 to 0.3) for PASC-CoRE + BrainHQ vs active comparator, 0.0 (95% CI, −0.2 to 0.2) for tDCS-active + BrainHQ vs tDCS-sham + BrainHQ, and 0.1 (95% CI, −0.1 to 0.3) for PASC-CoRE + BrainHQ vs BrainHQ alone. Secondary participant-reported outcomes and neuropsychological tests showed no differential benefits for any treatment arm. All 5 arms demonstrated some improvements over time on the modified ECog2 and on secondary outcomes. There were no serious adverse events attributable to the interventions. Conclusions and Relevance This phase 2 randomized clinical trial failed to demonstrate differential benefits for online cognitive training, a structured cognitive rehabilitation program, and tDCS for cognitive long COVID. Trial Registration ClinicalTrials.gov Identifier: NCT05965739 .

Abstract Chimeric antigen receptor (CAR) T-cell (CAR-T) treatment for B-cell acute lymphoblastic leukemia (ALL) induces high initial response rates, but most patients relapse. Low disease burden (often defined as <5% blasts in the bone marrow) is associated with better outcomes. CAR HEMATOTOX (HT) is a score using prelymphodepletion hematologic and inflammatory parameters to predict outcomes in lymphoma. Here, we assess its prognostic utility in a large multicenter adult B-cell ALL cohort. Patients who received brexucabtagene autoleucel across 33 centers in North America were included as part of the Real-World Outcomes Collaborative of CAR-T in Adult ALL (ROCCA) consortium. An independent cohort of 61 patients with ALL treated with an investigational CD19 CAR-T therapy at 1 center was also described. Among 199 ROCCA consortium patients, 43 (22%) patients with HTlow scores had lower rates of delayed neutrophil recovery than those with HThigh scores (26% vs 52%, P = .002) and fewer severe infections (2.5% vs 18.8%, P = .011). They also had higher response rates, overall survival (OS), and event-free survival (EFS), as well as lower nonrelapse mortality and cumulative incidence of relapse. The survival differences remained significant after multivariable adjustment for disease burden and other covariates. In the investigational cohort of 61 patients, patients with HTlow scores had improved OS and EFS, as well as higher peak CAR-T expansion. In summary, CAR HT score is a prognostic factor independent of disease burden in adult ALL. HTlow score is associated with superior outcomes after CD19 CAR-Ts and higher CAR-T expansion in a single-center cohort. These trials were registered at www.clinicaltrials.gov as #NCT01044069 and #NCT01860937.

BACKGROUND/OBJECTIVE Patient- and family-centered rounds (PFCR) have become a pediatric standard of care. However, rounds experiences of families using languages other than English (LOE)—particularly languages other than English or Spanish (LOES; eg, Arabic)—receive less focus. We aimed to identify differences in PFCR communication and engagement by language. METHODS We analyzed postintervention data from a 21-center structured PFCR study, assessing communication practices, quality, and family and nurse engagement during PFCR. Logistic regression adjusted by site compared PFCR between families using (1) LOE vs English, (2) Spanish vs English, and (3) LOES vs English. RESULTS Among 3051 PFCR encounters, 348 (11.4%) involved LOE (Spanish = 260; LOES = 85). Interpretation was not used in 7.2%, 5.8%, and 9.4% of encounters using LOE, Spanish, and LOES, respectively. PFCR in the following groups had lower adjusted odds (adjusted odds ratio [95% CI]) for the following domains: (1) LOE vs English: including providing verbal patient summaries (0.66 [0.46–0.95]), explaining diagnoses and differentials (0.62 [0.44–0.88]), family engagement (0.34 [0.20–0.57]), nursing inclusion (0.75 [0.60–0.93]), and nursing engagement (0.69 [0.52–0.90]). (2) Spanish vs English: diagnoses/differentials being explained (0.56 [0.37–0.85]), family engagement (0.35 [0.18–0.67]), nursing inclusion (0.77 [0.59–1.00]), and nursing engagement (0.68 [0.52–0.89]). (3) LOES vs English: families sharing concerns (0.66 [0.47–0.93]), family engagement (0.30 [0.16–0.54]), and nursing inclusion (0.74 [0.55–0.99]). CONCLUSION Even after implementing a PFCR intervention, families using LOE—especially LOES—experienced significant disparities in communication and engagement. Future approaches to improving PFCR should emphasize language access and promote nurse and family engagement for families using LOE, particularly LOES.

Background: Secondary shoulder deformities are the most frequent sequelae of upper trunk-type brachial plexus birth injury (BPBI). Coracoid process dysplasia was recently described as being associated with glenoid retroversion and was recognized to block successful humeral head relocation. There are little to no reports on coracoid process deformity causing anterior shoulder pain. Our hypothesis is that coracoid process impingement causes anterior shoulder pain in BPBI, which is relieved by coracoid excision. This study presents the short-term results of this new technique in BPBI patients. Methods: A retrospective review identified BPBI patients who underwent coracoid excision from 2000 to 2022. Indications for this procedure include BPBI patients with anterior shoulder pain limiting the range of motion, localized tenderness over a prominent coracoid process, a dysplastic coracoid process seen on imaging, and persistent pain despite activity modification, medication, and therapy. Patient characteristics, preoperative shoulder pain score, range of motion, degree of glenohumeral subluxation, patient-reported outcomes measurement information system (PROMIS) scores for pain interference, and physical and upper extremity function were collected from chart review. Postoperative pain scores, range of motion, and PROMIS scores were collected at an average of 1 year after excision. Results: Five upper trunk BPBI patients, ages 10 to 25 years old, with anterior shoulder pain underwent coracoid excision. All had statistically significant pain relief from 6.5–8.5/10 before to 0–3/10 after the procedure. Forward flexion and external rotation improved by an average of 18 degrees. The pain interference score decreased by 25%. There was a 33% improvement in physical function scores and a 31% increase in upper extremity function scores. No complications or recurrence were observed at 7.5 months to 1 year and 7 months after surgery. Conclusions: Coracoid excision is a simple procedure that can relieve localized shoulder pain caused by coracoid impingement in adolescent/adult BPBI. Continued follow-up of all patients will be undertaken to determine long-term recurrence rates and complications. Level of Evidence: Level IV.

TPS1138 Background: The SV-BR-1-GM breast cancer cell line activates anti-tumor immunity by expressing tumor associated antigens and secreting GM-CSF which enhances dendritic cell activation and promotes adaptive (T-cell mediated) and innate (dendritic and NK cell) immune responses. The cells are also engineered to optimize immune recognition through pt specific HLA antigen matching. SV-BR-1-GM acts through direct antigen presentation and CD4+ T-cell activation and, when combined w/ checkpoint inhibitors (CPIs), has demonstrated clinical benefit in 54 heavily pretreated metastatic breast cancer (MBC) pts. In pts w/ disease progression following CPI therapy, similar or improved progression free survival (PFS) compared to their prior treatment regimen. Disease control following antibody drug conjugates was observed in 40%of pts. Clinical benefit was seen in 5 out of 8 pts w/ untreated intracranial metastases. CD8+ Immuno-PET imaging suggests systemic activation, w/ increased CD8+ tumor infiltrating lymphocytes at both primary and metastatic tumor sites, as well as lymphoid organs. Optimized sequencing of CPI w/ SV-BR-1-GM and its latest phase 3 formulation have shown enhanced clinical outcomes, including improved overall survival (OS) (median 13.4 mos), PFS (3.6 mos), and clinical benefit rate (CBR; 61%).These findings have informed refinements to the ongoing pivotal, registration enabling Phase 3 trial, designed to optimize pt selection and treatment sequencing strategies. Methods: This ongoing multicenter, randomized, open label Phase 3 trial evaluates Bria-IMT + CPI vs. Treatment of Physician’s Choice (TPC) in MBC pts lacking approved curative therapies. Pts are randomized 1:1:1 to Bria-IMT + CPI, TPC, or Bria-IMT monotherapy (discontinued after 150 enrollments to prioritize combination arms). The Bria-IMT regimen consists of: Day -2: Cyclophosphamide 300 mg/m², Day 0: 20M irradiated SV-BR-1-GM cells, Day 2/3: 0.1 mcg pegylated α interferon at each inoculation site. CPI infusion is administered Day -3 to 3. Cycles q3w. TPC regimens follow site specific SOC. Imaging q6w (first 2 cycles), then q8w. Eligibility includes all MBC subtypes, including CNS mets, and permits prior CPI therapy ( >21 days pre-treatment). There will be 100 sites across the U.S., Canada, and ex-North America w/ an enrollment target of 404. The trial is currently active at 59 sites with 217 sub investigators. To date, 67 pts screened: 46 randomized (median age 56 yrs [34–83], median 6 [2–13] prior lines of therapy. The primary endpoint is OS, with an interim analysis at 144 events targeting a hazard ratio of 0.6. Secondary endpoints: PFS, overall response rate, CBR, CNS event free survival, and TWiST. Safety analyses ongoing; pt reported outcomes assess subjective treatment impact. Clinical trial information: NCT03328026 .