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Abstract Introduction The utilization of rear tip extenders (RTE) is often imperative during Inflatable Penile Prosthesis (IPP) placement. The impact of RTE on perioperative morbidity of IPP surgery is underexplored. Objective In this study, we assess intraoperative and postoperative outcomes among patients undergoing primary IPP implantation with or without RTE. Methods We performed a multicenter, retrospective analysis of men undergoing primary IPP placement between July 2016 and July 2021. A total of 4308 patients were identified, of which 2963 had no RTE and 1345 had RTE. After 1:1 propensity score matching for all confounding variables, 840 patients without RTE were compared to patients with RTE for intraoperative and postoperative outcomes. Chi-square and Mann–Whitney tests were used for statistical analysis for categorial and continuous variables respectively. For multivariable analysis, we used a forward stepwise model and included significant variables found on preoperative characteristics of patients. Kaplan–Meier time to event analysis were compared with Mantel-Cox log-rank test. Results Patients with RTE use had more postoperative complications (9.6% vs 5.2%, p < 0.001). More specifically, RTE patients had more episodes of postoperative hematoma and bleeding (2.0% vs 0.7%, p = 0.033), device malfunction (2.7% vs 1.8%, p = 0.006), and glans-related complications (0.8% vs 0, p = 0.015). On multivariable analysis, use of RTE (OR 1.58, 95% CI 1.07-2.34, p = 0.021), AMS 700 series device (OR 1.93, 95% CI 1.27-2.94, p = 0.002), penoscrotal approach (OR 2.60, 95% CI 1.61-4.18, p < 0.001), and older age (OR 1.02, 95% CI 1.00-1.04, p = 0.035) were associated with increased risk of postoperative complications. Patients with RTE use had increased rate of postoperative IPP revision (5.0% vs 2.1%, p = 0.002). The use of RTE (OR 1.71, 95% CI 1.00-2.90, p = 0.046), AMS 700 series device (OR 1.73, 95% CI 1.01-2.97, p = 0.048), penoscrotal approach (OR 3.16, 95% CI 1.63-6.17, p < 0.001), and history of Peyronie’s disease (OR 2.24, 95% CI 1.31-3.82, p = 0.003) were associated with increased risk of postoperative IPP revision or explantation. On Kaplan–Meier analysis, use of RTE was associated with increased risk of postoperative complications and IPP revision or explantation within 48 months (log rank p = 0.001 and p = 0.002 respectively). Conclusions In this large multi-institutional cohort, patients with RTE experienced more hematoma, device malfunctioning, and glans related post operative complications. The use of RTE is an independent predictor of post-operative complications and IPP revision or explanation. Disclosure No.

Objectives To evaluate the pre‐ and intraoperative variables that impact the integrity of the corporal bodies over time after inflatable penile prosthesis (IPP) placement, as predictors of intraoperative corporal perforation and delayed cylinder complications have not been well characterized. Patients and Methods We retrospectively reviewed a 16‐centre multi‐institutional database of IPP surgeries performed by experienced implanters from 2016 to 2021. Poor corporal integrity (PCI) was defined as intraoperative (iPCI) corporal complications or postoperative (pPCI) corporal complications. Multivariable analysis was performed to identify independent predictors of PCI, iPCI, and pPCI. Primary outcomes included intra‐ and postoperative corporal complications. Results We identified 5153 patients for analysis from 5406 IPP cases, finding 152 (2.95%) cases of PCI. On multivariable analysis, predictors of PCI included revision IPP surgery (odds ratio [OR] 8.16, 95% confidence interval [CI] 5.15–12.92; P < 0.001), sequential dilatation (OR 2.12, 95% CI 1.32–3.39; P = 0.002), coronary artery disease (CAD)/peripheral vascular disease (PVD) (OR 1.81, 95% CI 1.18–2.77; P = 0.006), older age (OR 1.02, 95% CI 1.01–1.04; P = 0.013), and corporal scarring (OR 1.58, 95% CI 1.0–2.5; P = 0.049). Predictors of iPCI included revision IPP surgery (OR 7.34, 95% CI 4.18–12.88; P < 0.001), corporal scarring (OR 2.77, 95% CI 1.64–4.69; P < 0.001), radiation therapy (OR 2.25, 95% CI 1.0–5.04; P = 0.049), and older age (OR 1.03, 95% CI 1.0–1.05; P = 0.025). Revision IPP surgery (OR 7.92, 95% CI 3.69–17.01; P < 0.001), sequential dilatation (OR 3.4, 95% CI 1.61–7.19; P = 0.001), CAD/PVD (OR 2.98, 95% CI 1.56–5.72; P = 0.001), and history of priapism (OR 3.59, 95% CI 1.08–11.99; P = 0.038) were predictive of pPCI. Conclusion Coronary artery disease/PVD, being of older age, having corporal scarring, undergoing IPP revision surgery and sequential dilatation were predictive risk factors for complications associated with PCI. Identifying patients who are at risk of having PCI may improve patient‐specific counselling, consideration of referral to more experienced implanters, and surgical planning to potentially promote longer‐term device viability.

Abstract Introduction Inflatable penile prosthesis (IPP) surgery is a well-established treatment for erectile dysfunction (ED). There is little information in the literature regarding the utilization of perioperative antimicrobial prophylaxis in primary and revision IPP surgeries. Objective We investigated the patterns of perioperative antimicrobial prophylaxis among a large multinational cohort of primary and revision IPP surgeries. Methods We conducted a retrospective analysis of 5400 patients (4187 primary IPP patients and 849 revision IPP patients) from our Prosthetic Urology Multi-Institutional Partnership (PUMP) institutions. Usage data for intravenous (IV), preoperative oral, and postoperative oral antimicrobials were analyzed. We specifically assessed patient profiles, antimicrobial selection, and antimicrobial duration. Multivariate statistical analyses were conducted to identify significant variations between primary and revision surgeries. Results For patients undergoing primary IPP placement, 81.9% received IV antibiotics for &lt;24 hours whereas 18.1% received IV antibiotics for &gt;24 hours. Preoperative oral antimicrobials were used in 59.4% of patients and 99.4% received postoperative oral antimicrobials. The overall infection rate for primary implants was 2%. Notably, quinolone administration shows a higher postoperative infection rate (11.4%) compared to gentamicin (1.9%), cephalosporin (0%), and vancomycin (1.0%). Multivariable regression analysis identifies factors such as a history of infection, diabetes, and priapism as predictors for postoperative infections. Furthermore, the study finds that perioperative antifungal use is associated with a decreased risk of infection. Conclusions This study provides valuable insights into the patterns of perioperative antimicrobial prophylaxis. Duration, type, and route of antibiotics given preoperatively or postoperatively do not affect postoperative infection rates among high volume prosthetic urologists. Giving IV antibiotics for more than 24 hours does not affect postoperative infection. Perioperative antifungals are a protective factor. Disclosure Any of the authors act as a consultant, employee or shareholder of an industry for: Coloplast, Clarus Therapeutics, Antares Pharma, Acerus.

Background: Splenic marginal zone lymphoma (SMZL) is a rare indolent disease with a median overall survival (OS) of more than 10 years, although a proportion of patients may develop aggressive histology transformation. In a previous report from this large, international dataset, the 10-year cumulative incidence of transformation was 17% (95% 13-21) and in another study of 186 patients, the 10-year cumulative incidence was 14%Click or tap here to enter text.. In this report, we focus on risk factors for transformation as well as clinical characteristics and outcomes of transformed SMZL (tSMZL). Patients and methods: Adults diagnosed with SMZL in 2000-2018 were identified through regional or nationwide population-based registries or from hospital registries. Only patients likely to have SMZL as defined by Matutes et al. were included. Those with discordant lymphoma and/or transformation at diagnosis were excluded. Medical records were reviewed by local clinicians with experience in hematology/oncology, and detailed information on clinical characteristics, treatment lines, and outcomes was collected. Only histologically confirmed high-grade transformations (HT) were included. OS was defined as the time from transformation to death or censoring at last follow-up. Additional analyses stratified by treatment exposure prior to HT and treatment of HT were conducted. Multivariable Cox analyses were performed to determine clinicopathological features associated with transformation and OS. Results: Out of 940 patients with SMZL, 111 developed HT during a median follow-up of 9.1 years. The median time from diagnosis to HT was 3.4 years with an interquartile range of 1.6-7.4 years. Median age at HT was 71 years. Patients with HT shared similar baseline characteristics to those without in terms of age at diagnosis (66.4 vs 67.6), f:m ratio (1.5 vs 1.1) and ECOG ³2 (7.2% vs 7.4%). The 5-yr OS from the time of HT was 42% (CI 95%, 32-54). Of the 111 patients with tSMZL, a complete treatment history from SMZL diagnosis until HT was available for 88 included in the following analyses. By the time of HT, 46 had not received any prior systemic therapy (37 only splenectomy, 9 no therapy), 6 patients had received rituximab alone or combined with splenectomy, and 36 patients had received chemotherapy alone or as part of combined modality treatment. In a uni- and multivariable models for HT, we assessed age, treatment at diagnosis, sex, extra-hilar lymphadenopathy, and extranodal involvement. In both the uni- and multivariable model, age &gt;70 (HR 1.9, 95% CI: 1.1-3.4), immediate treatment including splenectomy (HR 2.0, 95% CI: 1.05-3.6), and extra-hilar lymphadenopathy (HR 1.9, 95% CI: 1.1-3.3) were associated with higher HT hazard, while extranodal involvement (HR 0.23, 95% CI: 0.06-0.84) was associated with a lower HT hazard. At the time of first-line treatment, multivariable analysis revealed similar results and with no association between risk of transformation and treatment strategy (i.e splenectomy alone, rituximab monotherapy or chemotherapy with /without rituximab or splenectomy, and other). At the time of HT, patients who had been previously treated with chemotherapy had an inferior 5-year OS of 24% (95%CI: 13-44%) versus 54% (95%CI: 41-71%) for those who had not received chemotherapy prior to HT. In contrast, there was no difference in the survival of patients that transformed less than or more than 24 months from diagnosis with 5-year OS after HT of 35% (95%CI 20-60%) and 45% (95%CI, 33-61%) respectively. In a multivariable Cox regression analyses of age at time of HT, sex, time since last treatment &lt;24 months, chemo-exposure in previous treatment lines and anthracycline-containing therapy (+/-R) at the time of HT, only prior chemo-exposure was borderline associated with poorer OS (HR 1.8, 95%CI: 0.9-3.5). Conclusion: Patients with SMZL face a notable risk of developing tSMZL over time. Patients in need of immediate treatment at first SMZL diagnosis, age &gt;70 and extrahilar lymphadenopathy had a higher risk of tSMZL and outcomes at the time of HT were poor if patients had been exposed to prior chemotherapy after adjustment for age, sex, and time since last treatment.

BACKGROUND Our knowledge of how the genomic landscape of chronic lymphocytic leukemia (CLL) is impacted by the selective pressure imposed by chemotherapy and targeted agents remains incomplete. We hypothesize that the extent of clonal evolution, baseline transcriptional state, and the overall and clone-specific growth kinetics of CLL will vary under native conditions or following exposure to chemotherapy and targeted therapy. METHODS We report the systematic genomic analysis of leukemia-normal whole-exome sequencing (WES) of 420 samples collected from 170 patients who were &gt;65 years of age with treatment-naïve CLL. The treatment-cohort consisted of 83 patients who received ibrutinib (420mg daily) and 40 patients who received chlorambucil (0.5 mg/kg up to maximum 0.8 mg/kg, on days 1 and 15 of a 28-day cycle, up to 12 cycles) as part of the RESONATE-2 trial (NCT01722487). The ‘watch and wait’ (WW) cohort comprised 47 age-matched patients whose samples originated from the CLL Research Consortium and were untreated for their CLL during sampling. Sampling occurred at baseline and at day 300, and/or day 600, following initiation of therapy or following a diagnosis of CLL for those in the WW cohort. The WW cohort had more cases with a mutated IGHV (72% vs 40%), del17p (14% vs 0%), and del13q (72% vs 45%) when compared to the treatment cohort. Baseline CLL RNA-seq data were available for 150 patients. We used PhylogicNDT to reconstruct the clonal architecture from WES. By determining the fraction of cancer cells with each mutation (cancer cell fraction [CCF]) and their multiplicities (number of DNA molecules carrying a mutation per cancer cell), subclones were identified through clustering of CCFs of mutational events across samples from each patient. This allowed us to estimate the phylogenetic relationships and significant clonal shifts (defined as a distribution shift of CCF in a subclone of &gt;95% between two timepoints, corresponding to a median ΔCCF of 18%) for each patient's CLL and to relate these shifts to somatic and clinical features. RESULTS In total, we identified 791 subclonal clusters across the three patient cohorts (ibrutinib = 406, chlorambucil = 189, WW = 196). We observed higher rates of significant clonal shifts between any two time points in patients exposed to chlorambucil (68%, q=0.008) and ibrutinib (77%, q&lt;0.0001) when compared to patients on WW (36%). There was no significant difference in the number of patients exhibiting a clonal shift between those receiving ibrutinib and chlorambucil (q=0.3). More patients treated with ibrutinib (54%, q=0.0002) and chlorambucil (50%, q=0.004) harbored a clone that reduced in size than those on WW (17%). More patients treated with ibrutinib (71%, q&lt;0.0002) and chlorambucil (55%, q=0.12) possessed at least one clone that increased in size during therapy than patients receiving WW (34%). In ibrutinib-treated patients, SF3B1 mutations (q=0.13, 14% vs 5%) and XPO1 mutations (q=0.13, 5% vs 0.3%) were enriched in subclones that significantly reduced over the complete time period. We also observed more BIRC3 mutations in subclones that had a significant shift in CCF when compared to subclones that remained stable over time (q=0.2, 5% vs 2%). Consistent with the overall study, with 8 years of follow-up in this patient subset, long-term progression-free survival (PFS) was significantly higher in the patients treated with ibrutinib when compared to chlorambucil (P&lt;0.0001). This PFS benefit was also seen regardless of subclonal growth patterns. Using baseline RNA-seq data, we identified 7 of the 8 recently defined CLL expression clusters (EC), that were identified in the context of chemoimmunotherapy for CLL (Knisbacher et al. Nat Gen 2022), and could recapitulate the relationship to outcomes in individuals treated with chlorambucil. However, despite the larger cohort, no significant relationship between EC clusters and PFS were observed in ibrutinib-treated patients, suggesting that a distinct predictive baseline transcriptional signature may be present in ibrutinib-treated patients. CONCLUSION Our analyses highlight the need to interrogate the molecular features of CLL in relation to the impact of therapeutic selective pressure imposed by BTK inhibition, which appear distinct from exposure to chemotherapy. Ongoing analyses aim to identify relationships between patterns of growth and subclonal growth rates molecular and clinical features.

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 &lt; 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 &lt; 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 &lt; 5% were associated with improved PFS; prior ino exposure was negatively associated with PFS (p &lt; 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: NPM1 mutations, seen in up to 30% of adults with acute myeloid leukemia (AML), often co-occur with FLT3 internal tandem duplication (FLT3-ITD). Measurable residual disease (MRD) testing before allogeneic hematopoietic cell transplant (alloHCT) for persistence of mutated NPM1 and/or FLT3-ITD can identify patients with AML in complete remission (CR) at highest risk of relapse and death. Quantitative RT-PCR assays are currently recommended for NPM1 MRD testing, while FLT3-ITD MRD testing is DNA-based using next generation sequencing (NGS). DNA-based NGS assays for mutated NPM1 MRD testing may have several advantages but require validation. We performed NPM1 MRD detection in blood collected from patients with AML during first CR (CR1) prior to alloHCT on a subset of patients from the Pre-MEASURE study (PMID: 36881031) using a highly-sensitive, commercially available DNA-based NPM1 NGS MRD assay. Methods: Of the 531 patients aged 18 or older from the Pre-MEASURE study who received an alloHCT for NPM1mutated AML during CR1 at a CIBMTR reporting site in the USA between the years of 2013-2019, a subset of 190 were randomly selected to be included in this analysis. A commercially available research testing kit (IVS, Invivoscribe, San Diego, CA), which can detect DNA-based NPM1 MRD, was used to establish a workflow following clinical testing standards and validated to detect NPM1 insertion variants down to a variant allele fraction (VAF) of at least 0.005%. Results were compared to those previously reported using an anchored multiplex PCR-based (AMP) targeted NGS assay (detection limit 0.01%) and FLT3-ITD MRD results, where applicable. Overall survival (OS) and cumulative incidence of relapse were estimated with the day of transplant as time 0 using Kaplan-Meier estimation (log-rank tests), Fine and Gray model, and Cox proportional hazards models. Results: NPM1 NGS MRD testing was successful for 186 (98%) patients, of which 48 (26%) relapsed (median: 4.0 months; range: 0.7-52.5) and 64 (34%) died (median: 9.7 months; range: 0.4-58.9) post-alloHCT. The IVS assay detected NPM1 insertion variants in 71 patients with a median VAF of 0.0026% (range:0.0002-2.1%). Using a VAF threshold of ≥0.01% for MRD positivity, the IVS test showed that 24 patients tested positive for NPM1 MRD pre-alloHCT, which was associated with significantly increased rates of relapse (52% vs 20% at 3yrs; HR=4.3; P&lt;0.001) and decreased OS (34% vs 71% at 3yrs; HR=3.6; P&lt;0.001) compared to testing negative, in close alignment with those previously reported using the AMP assay. After removing the VAF threshold, an additional 47 patients were classified as NPM1 MRD positive, which remained associated with increased rates of relapse (40% vs 15% at 3yrs; HR=3.4; P&lt;0.001) and decreased OS (50% vs 75% at 3yrs; HR=2.9; P&lt;0.001). In multivariable analysis, residual NPM1 MRD burden prior to alloHCT was associated with risk of relapse and death in a dose-dependent manner. Patients were further subdivided based on their reported FLT3-ITD mutational status at baseline. Increased risk of relapse was seen for NPM1 MRD positive patients regardless of baseline FLT3-ITD. 123 (66%) patients were co-mutated for FLT3-ITD at baseline and previously tested for FLT3-ITD MRD using the IVS assay (PMID: 38696205). Defining MRD based on the presence of NPM1 vs NPM1 and/or FLT3-ITD revealed equivalent levels of relapse (45% vs 44%) and OS (45% vs 46%) at 3 years, with NPM1 MRD evaluation identifying 5 additional relapses. These results were confirmed in the full Pre-MEASURE cohort (n=317) using the AMP assay. NPM1 MRD positive patients receiving nonmyeloablative conditioning or reduced-intensity conditioning (RIC) without melphalan (mel) had increased risk of relapse or death compared to patients receiving myeloablative conditioning or RIC with mel, regardless of FLT3-ITD co-mutational status (3yrs: relapse 87% vs 55%, P=0.006; OS 15% vs 42%, P=0.013). Conclusions: In patients with NPM1 mutated AML from the Pre-MEASURE study, we show that detection of residual NPM1 variants in pre-transplant blood during CR1 using a highly sensitive DNA-based assay is associated in a dose-dependent manner with a significantly increased risk of relapse and death after allo-HCT, which can be mitigated in part by conditioning regimen. In patients co-mutated for both FLT3-ITD and NPM1 at diagnosis, NPM1 should be prioritized as a target for NGS-MRD if only one test is available.

Introduction E1910 randomized pts with ALL aged 30-70 years who were measurable residual disease negative (MRD-) by multi-color flow cytometry (FC) after intensification to conventional chemotherapy (chemo) with or without blinatumomab (blina). The addition of blina resulted in improved overall survival (OS) (Litzow, NEJM 2024) and led to a new standard of care. Older ALL pts have inferior outcomes when compared to younger pts in part due to increased treatment toxicity. In E1910, exposure to dexamethasone and pegasparagase was reduced for older pts (age &gt;55 years). We present results of subgroup analyses describing outcomes of older pts enrolled in E1910. Methods Details of the E1910 protocol remission induction (step 1), high dose methotrexate with pegaspargase intensification (step 2), blina randomization (step 3), and maintenance (step 4) or allogeneic hematopoietic stem cell transplant (HCT) were previously presented (Litzow, NEJM 2024). MRD status was determined after step 2 centrally with 6-color FC with MRD- defined as &lt;0.01% in the bone marrow (BM). Following approval of blina in the US for MRD positive (MRD+) disease in 2018, MRD+ pts were assigned to the blina arm and no longer randomized. The primary objective was to compare the OS and relapse free survival (RFS) among older pts aged &gt;55 years (pre-specified stratification factor) who received chemo + blina to that of pts who received chemo alone (step 3 treatment). Estimates of OS and RFS were calculated using the Kaplan-Meier method. Comparison of OS and RFS between treatment arms was conducted using the two-sided stratified log-rank test and Cox model with CD20 status, rituximab use, and whether pts intended to receive HCT or not as stratification factors. Stratified Multivariate Cox models of OS and RFS were used to further evaluate the effect of step 3 treatment, adjusted by gender, white blood cell count (WBC), platelets, hemoglobin, peripheral blood blasts, BM blasts, performance status and combined molecular risk category. Results Among the 488 enrolled pts, 211 were ≥55 years old with median age of 61 (range 55-70). Among older pts, 49.3% were female and 83.4% were white, 17 (8.1%) pts had WBC &gt;30.000/uL at the time of diagnosis. 156 (73.9%) pts had CD10+ early B-ALL and 46 (21.8%) had CD10- B-ALL immunophenotype. The most common genetic subgroups were low hypodiploid (n=58, 27.5%), BCR::ABL1-like (n=34, 16.1%) and KMT2A rearranged (n=26, 12.3%). 8.1% of pts had low, 9.0% intermediate, 63.5% high combined molecular risk disease and in 19.4% of pts risk could not be assigned. Baseline characteristics were not significantly different in chemo + blina and chemo only pts. The median follow-up for this analysis from step 1 registration was 54.6 months. Complete response with (CR) or without (CRi) count recovery after induction was observed in 174 (82.5%) pts (167 CR, 7 CRi). 93 (44%) pts were MRD-. 32 (15.1%) pts received HCT on study and 24 (11.4%) pts received it off study. Among MRD- pts (n=93), 46 were randomized to and 45 received blina: 6 (13.3%) pts had 1, 14 (31.1%) had 2, 2 (4.4%) had 3 and 23 (51.1%) had 4 cycles. 3-year OS were 71% and 67% for the blina and the chemo only arm (univariate model: HR 0.75, 95% CI: 0.37-1.50; multivariate model: HR 0.56, 95% CI: 0.25-1.27). 3-year RFS were 69% and 59% for the blina and the chemo only arm (univariate model: HR 0.75, 95% CI: 0.39-1.45; multivariate model: HR 0.67, 95% CI: 0.32-1.42). Among MRD+ pts (n=25), 14 were randomized to and 11 received blina: 7 (63.6%) pts had 2, and 4 (36.4%) had 4 cycles. 3-year OS were 66% and 44% for the blina vs the chemo only arm (univariate model: HR 0.66, 95% CI: 0.12-3.64). 3-year RFS were 64% and 31% for the blina vs the chemo only arm (univariate model: HR 0.64, 95% CI: 0.15-2.74). Frequency of treatment-related toxicities among older pts during different study phases and treatment assignments will be presented. Conclusion Despite evidence of improved outcomes in the whole study cohort, the addition of blina to consolidation chemo for older pts with ALL was not associated with statistically significant improvement of OS or RFS in this exploratory analysis not powered to detect the difference in subgroups. This is possibly due to sample size but may be due to biologic differences in the older adult population. Further studies are needed to definitively determine tolerance and benefit of blina addition to consolidation for older pts with ALL.

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 &gt;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 &lt;60 yo; p=0.004). Pre-apheresis, 33 pts (45%) had active disease (&gt;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 &lt;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 &lt;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 &lt;60, p=0.049). Grade 3-4 ICANS were similar between the groups: 33%, 27% and 29% in the ≥70, 60-69, and &lt;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 &lt;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 &lt;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 &lt;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 &lt;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 &lt;60, p=0.14) or 12-months OS (61% in ≥ 70 vs. 69% in 60-69 vs. 73% in &lt;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.

Primary resistance to BCMA-directed bispecific antibodies (BCMA-BsAb) is a major clinical hurdle despite their outstanding efficacy for relapsed and refractory multiple myeloma (MM). Primary resistance has been linked clinically to patient characteristics including tumor burden. Our previous work in the immunocompetent Vk*MYC model of MM credentialed that tumor burden also correlates with resistance to a murine BCMA-BsAb, which we addressed through drug combinations with MM backbone agents. Pairing the BsAb with cyclophosphamide (Cy) was well-tolerated, reversed primary resistance, reshaped an immunosuppressive tumor microenvironment (TME) and led to durable responses with immunosurveillance in all but the most aggressive settings. Here, we aimed to improve the BCMA-BsAb and Cy combination strategy with a goal of curing models representing clinically relevant Cy-refractory aggressive settings, by adding T cell checkpoint blockade. Despite a lack of single agent activity of checkpoint inhibitors in MM (and in our models), PD1 and TIGIT are relevant targets as their expression on T cells correlates with both primary and acquired resistance to BCMA-directed cell therapies. Our team hypothesized that blockade of either PD1 or TIGIT with concurrent BCMA-BsAb and Cy would deepen anti-MM responses and provide a more durable immunotherapy regimen by sustaining activation of the T cell repertoire. Methods: We preclinically tested the ability of two weeks of concurrent dosing of BCMA-BsAb with Cy, checkpoint inhibitors targeting either PD1 or TIGIT, or the triple combination to overcome primary resistance and improve survival in a Cy-resistant transplantable Vk*MYC model of MM. We followed the response longitudinally in the blood, and in the bone marrow and spleen after complete responses were achieved at five weeks. Results: The double combination of a checkpoint inhibitor to the BCMA-BsAb was well-tolerated and abolished primary resistance, yet, failed to provide curative responses. Whereas the triple combination with either PD1 or TIGIT blockade remained safe, provided robust initial responses that overcame primary resistance and resulted in durable complete and curative responses in the entire cohort. These survival benefits represent significant improvements over control combinations tested here but also over all historical preclinical anti-MM therapy tested in our models to date. Both PD1 and TIGIT blockade with Cy/BCMA-BsAb triple combinations delivered a similar multiphasic potent anti-tumor response. This response was first characterized by highly effective T cell-mediated lysis of the tumor, as evidenced by deep reduction of M-spike after two weeks of treatment. As we previously published, the addition of Cy to BCMA-BsAb rapidly reshapes the TME by depleting Tregs and exhausted T cells and brings naive T cells to the tumor. However, we observed elevated T cell checkpoint expression at times of BsAb-relapse in aggressive models, suggesting that blockade of these pathways may help sustain T cell activation. Indeed, the ensuing T cell response in the triple combination gradually builds and encourages a pool of less terminally differentiated T cells to proliferate to allow for a more sustained response with repeat dosing. For the first time, we observe that the triple combination significantly engages the CD4 T cell compartment, which can be essential for a complete anti-tumor response. At the time of complete response, single cell analysis displays that T cells retained in the BM were less exhausted and defined by elevated CCR2 expression, a known marker of activated memory T cells, suggestive of ongoing immunosurveillance. Conclusions: Here we demonstrated through controlled in vivo experimentation how the addition of Cy reverts primary resistance to BCMA-BsAb by reshaping the TME in our Cy-insensitive preclinical model. Adding checkpoint inhibitors targeting TIGIT or PD1 further improves the durability of BsAb and Cy combination to cure all mice in these cohorts, by critically lysing the tumor, resetting the suppressive TME, and instigating a gradual, multiphasic, and sustained anti-MM T cell response. The concurrently delivered triple combination is well tolerated and provides optimal temporal control of MM especially in a preclinical model reflecting primary resistance mediated by high tumor burden and may have translational benefit to MM patients.