Citations

Abstract Immune checkpoint inhibitor–associated immune thrombocytopenia (ICI-ITP) has been described in case reports and small case series, but comprehensive data on its incidence, risk factors, clinical features, treatment, and outcomes are lacking. We reviewed medical records of all adults initiating ICI therapy between 2016 and 2023 at 29 US hospitals across 7 major cancer centers to identify patients with ICI-ITP. Multivariable logistic regression was used to identify risk factors, and Cox modeling was performed to assess the association between ICI-ITP, its severity, and mortality. Among 86 467 patients, ICI-ITP occurred in 214 (0.25%). Independent risk factors included lower baseline platelet count, combination ICI therapy, stage IV cancer, and additional immune-related adverse events. ICI-ITP occurred at a median of 8 weeks (interquartile range [IQR], 4-18) after ICI initiation, with a median nadir platelet count of 41 × 109/L (IQR, 17 × 109/L to 64 × 109/L). Patients were treated with glucocorticoids (n = 106 [49.5%]), immune globulin (n = 39 [18.2%]), and thrombopoietin receptor agonists (n = 29 [13.6%]). Recovery occurred in 161 patients (75.2%) at a median of 2.3 weeks (IQR, 1.0-5.3). Of 76 patients rechallenged with ICIs, 23 (30.3%) developed recurrent ICI-ITP. ICI-ITP and its severity were associated with higher all-cause mortality, with a nearly threefold increase in risk among patients with severe ICI-ITP than those without ICI-ITP (adjusted hazard ratio, 2.96 [95% confidence interval, 2.14-4.08]). These findings establish ICI-ITP as a rare but clinically significant complication of ICI therapy, provide, to our knowledge, the first large-scale description of its risk factors and clinical course, and underscore the importance of timely recognition and management.

Abstract Background The purpose of this study was to develop a series of benchmarks specifically for large language model (LLM) performance in the identification of drug-drug interactions (DDIs). Methods We evaluated six LLMs using a clinician-designed dataset of 750 DDI scenarios. Tasks included: (1) a pointwise two-drug classification task (2) a pairwise three-drug discrimination task and (3) a listwise 4–6 drug selection task. Zero-shot prompting was applied and performance was assessed using precision, recall, F1 score, accuracy, and self-consistency. Results Model performance varied by task structure and interaction severity. GPT-5-Chat demonstrated the highest recall and F1 score in the pointwise task (80.7% and 80.2%), whereas DrugGPT achieved superior accuracy in the pairwise (93.7%) and listwise task (92.6%). All models had improved performance with more severe compared to less severe DDIs (accuracy 72.0-99.2% vs. 58.3-86.7%). All models tended to have higher self-consistency in the pairwise and listwise experiments compared to the pointwise experiment (68.8-93.6% vs. 31.0-74.2%). No model exhibited uniformly high reliability across all tasks. Conclusions Current LLMs show inconsistent capabilities in identifying DDIs. Performance degrades as reasoning space expands with limited stability. These findings emphasize the need for multi-format evaluation frameworks and reliability-aware assessment when considering LLMs for medication-safety applications.

ABSTRACT Background Older adults are at high risk for severe injuries and death from falls. Physical therapist (PT) and occupational therapist (OT) evaluations have been introduced into Emergency Department (ED) care to assist with fall risk evaluation and fall prevention care. An evaluation of current evidence was undertaken to inform the Geriatric ED Guidelines 2.0. Methods Systematic review of physical and/or occupational therapy evaluation for fall prevention in the ED. The intervention was evaluation by a rehabilitation therapist (PT, OT, or both) for fall prevention, fall assessment, or mitigation of fall risk factors. Studies that did not perform the evaluation during the ED or ED Observation Unit visit were excluded, such as referrals for home consultation. The published literature was searched using strategies created by a medical librarian and was implemented in Embase and PubMed in March 2025. Covidence was used for article collation and review. Risk of bias was assessed using the Cochrane Risk of Bias v2 and the Ottawa–Newcastle scale. Results The search resulted in 387 articles with 52 duplicates, for 335 unique citations. Ten articles on 6 datasets were included (4 abstracts and 6 published manuscripts). One article was at high risk of bias as very few intervention patients received therapist evaluation. The remaining 5 datasets had varied co‐interventions in addition to PT and/or OT evaluations. PT or OT evaluation in the ED was associated with reduced ED revisits at 1, 2, and 6 months. Evaluations in the ED were not associated with increased hospital admission rates or ED length of stay. A meta‐analysis was infeasible due to varied outcome timeframes. Conclusions PT and/or OT evaluations for fall prevention were associated with reduced subsequent ED revisits for older adults. However, the impact of co‐interventions and heterogeneity limits strong conclusions.

Background. As cancer therapeutics improve, more liver transplant (LT) candidates will have a history of prior to transplant malignancy (PTM), an established risk for cancer posttransplant. Methods. This study provides granular analysis (with focus on nonliver PTM) of posttransplant cancer risk relating to PTM in 1105 consecutive adult LT recipients (2009–2019, N = 542 with PTM). Results. PTM prevalence increased from 37.8% to 63.2% during this timeframe. Post-LT survival was lower (10 y: 61.2% versus 75.1%; P < 0.001) with higher cancer-related mortality (17.6% versus 2.2%; P < 0.001) in patients with any PTM. The higher cumulative incidence of cancer post-LT associated with PTM (59.7% versus 37.6%; P < 0.001) was not attributable to de novo cancer (38.5% versus 37.7%; P = 0.21) but to recurrence. Cancer recurrence rate (10 y) was lowest in nonliver/nonskin (“other”) PTM (10.6%) with mortality rates from recurrence of only 4% in this cohort. De novo cancers may present at more advanced stage in patients with PTM and lung cancer the most common nonskin de novo malignancy (PTM 21%, no PTM 7%). Family history of cancer was an independent predictor for de novo cancer. Conclusions. PTM associated post-LT cancer outcomes are dominated by skin and liver cancer recurrence and not recurrence of “other” cancers or de novo cancer. This data supports the guidance proposals for cautious liberalization of “other” cancer remission requirements before transplantation. As post-LT cancer is highly prevalent regardless of PTM status, adherence to posttransplant cancer screening and surveillance is critical to identify early cancer after transplant.

Abstract Background: Routine laboratory testing prior to chemotherapy administration is a cornerstone of hematology and oncology practice, aimed at ensuring the safety and efficacy of treatment. However, over time, standardized protocols may accumulate excessive or low-yield laboratory tests that offer limited value to clinical decision-making. In 2018, Mayo Clinic implemented standardized treatment protocols using Epic Beacon, an electronic health record module that integrates chemotherapy regimens with associated laboratory testing and clinical workflows. While well-intentioned, these protocols may include redundant tests that delay treatment initiation, increase patient discomfort and anxiety, and burden providers with excessive in-basket communications. We hypothesize that many laboratory tests currently embedded within prechemotherapy workflows are unnecessary and can be safely omitted without compromising patient care. Methods: We conducted a retrospective cohort study evaluating the pre-treatment laboratory testing associated with the R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) chemotherapy protocol within the Mayo Clinic Rochester Division of Hematology. The study included 100 patients diagnosed with diffuse large B-cell lymphoma who received treatment between January 1 and December 31, 2024. Patients were excluded if they had incomplete medical records or received treatment outside the Mayo Clinic system. Data was abstracted via chart review using the Mayo Data Explorer. We analyzed complete blood counts (CBC), which include 12 individual tests, and comprehensive metabolic panels (CMP), which include 16 individual tests, obtained prior to each treatment cycle. For each cycle, we assessed the proportion of abnormal laboratory results and the proportion of abnormal results deemed clinically relevant which were defined as those that prompted a treatment delay, dose reduction or early termination of a cycle. Results: The cohort comprised 100 patients with a mean age of 68.2 years (SD 13.4) and a median age of 71 years (IQR 58.75–77); 57 were male and 43 were female. Based on available documentation, disease stage was classified as limited (stage I/II; n=41) or extensive (stage III/IV; n=59). A total of 519 R-CHOP cycles were administered, including 419 subsequent cycles (cycles 2–6). Fifteen patients discontinued treatment early, although none of the discontinuations were attributable to abnormalities in pre-infusion laboratory testing. Among the 419 subsequent cycles, 34 (8.1%) experienced treatment delays, with only one delay resulting from a clinically significant laboratory abnormality (hyperglycemia). Additionally, 23 patients underwent regimen modification (dose reduction or drug holding), but none of these were due to pre-infusion lab abnormalities.Of the 411 comprehensive metabolic panels (CMPs) obtained prior to these cycles, 315 (76.6%) contained at least one abnormal value, yielding a total of 786 abnormal results. Similarly, 405 of 415 (97.6%) complete blood counts (CBCs) demonstrated at least one abnormality, generating 2,696 abnormal values in total. Despite the high frequency of abnormal findings, the overall clinical yield was minimal, with only 1 of 826 pre-infusion laboratory panels (0.12%) leading to a modification in clinical management. Conclusion: Routine pre-infusion laboratory testing prior to R-CHOP chemotherapy frequently identifies abnormal results. However, these abnormalities are rarely clinically significant and do not affect treatment decisions. These findings support the reconsideration of current testing protocols to reduce unnecessary testing, enhance workflow efficiency, and minimize patient and provider burden without compromising safety.

Abstract Introduction: Patients with triple-class exposed (TCE) relapsed/refractory multiple myeloma (RRMM) have historically experienced poor clinical outcomes, prompting the development of novel therapeutic options. Idecabtagene vicleucel (ide-cel) was the first chimeric antigen receptor (CAR) T cell therapy approved for this population, while teclistamab became the first approved bispecific antibody. Both target B-cell maturation antigen (BCMA) and are increasingly used in real-world (RW) settings. Most comparative evidence to date is derived from single-arm clinical trials with cross-trial adjustments. RW studies offer an opportunity to directly compare these therapies and assess their relative effectiveness in routine clinical practice. Methods: We conducted a comparative effectiveness analysis of ide-cel and teclistamab in patients with TCE RRMM using RW data from the United States Flatiron Health electronic health record-derived, deidentified database (January 2011 to April 2025 data cut). Adults who received either index therapy at any line of treatment after becoming TCE (ie, previously exposed to an immunomodulatory agent, a proteasome inhibitor, and an anti-CD38 monoclonal antibody) were included. Exclusion criteria were prior exposure to CAR T cell therapy, bispecific antibodies, or belantamab mafodotin; absence of index treatment; or lack of post-index follow-up. Index dates (T0) represent the date of infusion for ide-cel and the start of treatment for teclistamab. Seventeen prognostic covariates were selected a priori based on published rankings and used to balance treatment groups via inverse probability of treatment weighting (IPTW) with average treatment effect weights. Cox proportional hazards models were used to estimate unadjusted and IPTW-adjusted HRs with 95% CIs for progression-free survival (PFS) and overall survival (OS). As the ide-cel cohort only included infused patients, additional analyses were performed to emulate a real-world intention-to-treat population given the potential immortal time bias (patients in the ide-cel cohort were required to survive between apheresis and infusion). Specifically, patients in the teclistamab cohort who died within the first 24 days (median turnaround time for ide-cel manufacturing in United States in 2024) were excluded and 2 scenarios were performed to re-align T0 based on this 24-day period (either shifting teclistamab T0 forward or ide-cel T0 backward). Lastly, sensitivity analyses assessed differences in restricted mean survival time (dRMST) at 12 and 24 months. Results: A total of 281 patients met the inclusion criteria (ide-cel, N=106; teclistamab, N=175), with median follow-up of 22.4 and 13.7 months, respectively. IPTW adjustment balanced all covariates between groups (effective sample size: ide-cel, n=68; teclistamab, n=135). Adjusted analyses showed improved PFS with ide-cel versus teclistamab (HR, 0.67; 95% CI, 0.47–0.97), with median PFS of 11.3 versus 6.5 months. OS was also improved with ide-cel (HR, 0.59; 95% CI, 0.35–0.98); median OS was not reached in either group due to insufficient follow-up. There was a consistent trend of HRs favoring ide-cel versus teclistamab for both PFS and OS in both scenario analyses addressing the potential immortal time bias. Further, sensitivity analyses using dRMST confirmed statistically significant improvements in both PFS and OS with ide-cel across all scenarios at all time points evaluated. Conclusions: In this RW analysis, ide-cel was associated with superior PFS and OS compared with teclistamab in patients with TCE RRMM. These findings support emerging RW evidence favoring BCMA-directed CAR T cell therapies over bispecific antibodies and may inform treatment sequencing decisions in this high-risk population.

Abstract BACKGROUND Children exposed to poverty during frontline therapy for B-lymphoblastic leukemia (B-ALL) experience inferior overall survival (OS), higher relapse rates, and earlier relapse than their peers. Real-world data describing treatment patterns and survival after relapse of B-ALL are lacking and, as a result, the impact of poverty following relapse remains poorly understood. This study evaluated the association of poverty exposure, proxied by insurance status, with post-relapse survival and explored potential explanatory mechanisms, including disease biology and therapy utilization. METHODS Data from Retrospective Study of Contemporary Approaches to First Relapse in B-ALL (ReCALL-1), a multicenter retrospective cohort study of patients &lt; 30 years old with first relapse of B-ALL from 2018-2022, were used. The primary exposure was poverty, proxied by insurance status at relapse, categorized as any private insurance (poverty unexposed), public-only insurance (poverty exposed), no insurance, or unknown; the latter two were not included in comparative analyses due to low numbers. The primary outcome was OS. Secondary outcomes included measurable residual disease (MRD)-negative second complete remission (CR2), relapse after CR2, non-relapse mortality (NRM), with relapse treated as a competing risk, and receipt of cellular and immunotherapies. RESULTS Among 462 patients from 31 U.S. institutions, 41% had private insurance, 47% public-only insurance, 2% no insurance, and 10% unknown. Compared to privately insured patients, those with public insurance were more likely to be Hispanic (56% vs 19%, p&lt;0.001) and have non-English preferred language (30% vs 6%, p&lt;0.001). Non-Hispanic Black patients comprised 9% of those with public insurance and 5% of those with private insurance. Disease characteristics that differed by insurance status at relapse included: Ph-like cytogenetics, more common in publicly insured (23% vs 11%, p=0.002), and infant ALL, more common in privately insured patients (10% vs 5%, p=0.06). Publicly insured patients were more likely to have experienced major organ toxicity during frontline therapy (32% vs 18%, p=0.002) and very early relapse (&lt;18m from diagnosis: 43% vs 32%, p=0.07). Other demographic and disease characteristics, including relapse site and cytomolecular features, were similar by insurance status. With a median follow-up of 51 months from relapse, 4-year OS differed by insurance (log-rank p=0.02): 72% for private vs 56% for public insurance. After adjusting for race/ethnicity and language, public insurance increased the hazard of death by 65% (aHR 1.65 95% CI 1.13-2.42, p=0.004). The association remained, but was attenuated, when unbalanced disease characteristics (time to relapse, infant ALL, Ph-like cytogenetics, prior organ dysfunction) were included (aHR 1.47, 95% CI 1.00-2.16, p=0.05). Rates of MRD-negative CR2 were similar (85% public vs 87% private). However, point estimates suggested publicly insured patients had more relapse after CR2 (44% vs 37%, p=0.42) and higher 4-year NRM (16% vs 10%, Gray's test p=0.12), though neither were significant. Treatment choices for first relapse did not differ by insurance status. Utilization of intensive reinduction (91% vs 95% for public vs private, p=0.18) and clinical trial enrollment (22% for both) were similar. Receipt of cellular therapies did not significantly differ by public vs private insurance: Chimeric Antigen Receptor-T cells (CAR-T: 38% vs 34%, p=0.41), hematopoietic cell transplant (HCT: 42% vs 47%, p=0.32). Use of blinatumomab trended higher in those with private insurance (36% vs 45%, p=0.07), and inotuzumab was similar (11% for both, p=0.87). Median time from relapse to CAR-T or HCT was comparable (to CAR-T 102 vs 100 days, to HCT 117 vs 114 days). CONCLUSION This is the first study to demonstrate differential survival by insurance type, a proxy for poverty exposure, after first relapse of B-ALL. In this large multicenter, real-world cohort, patients with public insurance had worse OS after relapse than those with private insurance. The survival disparity existed independent of other SDOH factors. Adjustment for known high-risk disease features only partially accounted for the observed differences in OS. In contrast, rates of MRD-negative CR2 and receipt of CAR-T and HCT were comparable across insurance types. These findings highlight the urgent need to identify effective interventions that will ensure equitable outcomes after relapse.

Abstract Introduction: Ciltacabtagene autoleucel (cilta-cel) is a highly effective BCMA-redirected CAR T-cell therapy for RRMM. While the pivotal CARTITUDE-1 trial established a target dose of 0.75 x 10^6 CAR+ viable T-cells/kg, the approved cell dose is 0.5-1.0 x 10^6 and the optimal dosing strategy to balance efficacy and toxicity remains unclear. This question is of interest given that a dose-response association has been demonstrated for idecabtagene vicleucel (a related BCMA-directed CAR T product). It has also been hypothesized that lower doses of cilta-cel may be associated with reduced toxicity. This study aims to evaluate the association between cilta-cel dose and key efficacy and toxicity outcomes using a large, real-world dataset from the US Multiple Myeloma Immunotherapy Consortium. Methods: We conducted a multicenter, retrospective analysis of 751 RRMM patients treated with commercial cilta-cel across 15 US academic centers. The administered cilta-cel dose (million cells/kg) was categorized into four groups: low (&lt;0.5), standard-low (0.5 to &lt;0.6), standard (0.6 to &lt;0.8), and standard-high (0.8 to 1.0). We compared incidence rates of cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), delayed neurotoxicity (DNT), and immune effector cell-associated hemophagocytic lymphohistiocytosis-like syndrome (IEC-HS) across these dose categories using logistic regression. Best response rates and progression-free survival (PFS), estimated using the Kaplan-Meier method, were also compared, with differences assessed using the log-rank test for the latter. Results presented are derived from multivariable models adjusting for extramedullary disease, ECOG status, penta-refractory disease and receipt of bridging therapy. Results: Among 751 infused patients, the dose distribution was: &lt;0.5 (n=33), 0.5 to &lt;0.6 (n=131), 0.6 to &lt;0.8 (n=550), and 0.8 to 1.0 (n=37). The four dose groups were well-balanced in terms of baseline patient and disease characteristics, including age, high-risk cytogenetics, and extramedullary disease, with the exception of t(14;16), which was more common in the standard-low and standard dose groups (p=0.006). There were no statistically significant differences in the rates of any grade CRS (p=0.11), any grade ICANS (p=0.84), grade ≥3 ICANS (p=0.36), duration of CRS (p=0.18) or ICANS (p=0.64), or IEC-HS (p=0.16) across the four dose categories. Time to onset of CRS was shorter for the standard-high dose compared to the low dose (6 days vs. 8 days; p=0.08). Importantly, there was no significant difference in the rate of DNT (3.0%, 9.2%, 8.8%, 5.4%; p=0.24). Similarly, there was no significant difference in overall response rates (97%, 96%, 96%, 88%; p=0.50) or complete response rates (75%, 65%, 75%, 66%; p=0.10) by dose. The median follow-up was 12.3 months (IQR: 6.9, 20.5). For patients who received a standard-low dose (0.5, 0.6), the median PFS was 17.5 (IQR: 13.5, NR) months. For the standard dose range of (0.6, 0.8), the median PFS was 28.7 (95% CI: 19.8, NR) months, while the median PFS for the standard-high dose (0.8, 1.0) was not reached. For the low dose range of &lt;0.5, the median follow up was only 8.7 months, which did not allow reliable estimation of the median PFS. While the overall difference in PFS among the groups did not reach statistical significance by the log rank test, there was a clear trend toward improved PFS with higher cell doses in the multivariable model, with outcomes clearly ordered in the same direction as the cell dose categories. A similar trend was also evident in the rates of 12-month PFS which showed an improvement with increasing dose (62% ,67%, 73%, 80%). Conclusions: In this large, real-world cohort of RRMM patients treated with cilta-cel, a lower cell dose was not associated with reduced incidence or severity of CRS, ICANS, DNT, or IEC-HS. Conversely, a dose-response correlation with PFS was observed, with higher doses trending toward longer median and 12-month PFS. It remains unknown if a lower cell dose in the commercial setting reflects poor T cell quality, yet these findings suggest that dose reduction of cilta-cel may not be an effective strategy to mitigate toxicities and might be associated with a trend toward lower efficacy. Therefore, the standard target dose should be utilized to maximize patient outcomes and further prospective dose exploration is warranted.

Abstract Background: CD19-directed CART cell (CART19) therapy has transformed the treatment of B-cell malignancies but is limited by life-threatening toxicities, including cytokine release syndrome (CRS) and immune effector cell–associated neurotoxicity syndrome (ICANS), as well as low durable remission rates. Our understanding of the pathogenesis of CART-associated toxicities is limited, and although current treatments are effective, refractory cases remain challenging. Methods and Results: To investigate CRS/ICANS pathogenesis and identify new therapeutic targets, we analyzed plasma cytokine kinetics within the first month of CART19 cell therapy in 25 relapsed/refractory (r/r) large B-cell lymphoma (LBCL) and 14 r/r follicular lymphoma (FL) patients (NCT02030834). In this cohort, 22 (88%) patients developed any-grade CRS (73% LBCL, 27% FL) and 4 (16%) developed any-grade ICANS (50% LBCL, 50% FL). Across 30 analyzed cytokines, IL-5 emerged as the second most enriched cytokine based on the median peak-to-baseline (Day 0) ratio in patients who experienced CRS vs. those who did not. The IL-5 ratio was 6.6-fold higher (p&lt;0.05) and 11.9-fold higher (p=0.093) in patients who experienced CRS or ICANS, respectively. Moreover, IL-5 was elevated in patients experiencing CRS on Days 1 and 2 (p&lt;0.05). Prompted by our results, we evaluated the effect of IL-5 neutralization with a monoclonal antibody (mAb) on CART-associated toxicity in a patient-derived B-acute lymphoblastic leukemia (B-ALL) xenograft model. After engraftment (average of 110 human CD19+ cells/µL peripheral blood), NSG mice were randomized based on tumor burden and treated with 3.5×10⁶ CART19 plus either IL-5 mAb or IgG control (10 mg/kg, weekly), or no treatment. Mice receiving IL-5 mAb showed reduced weight loss (p&lt;0.005, Days 13–16) and neuroscore (p&lt;0.05, Day 15), as assessed by a daily, blinded 18-point assessment, vs. the IgG group. Additionally, while CRS-associated cytokines (GM-CSF, IFN-γ, MIP-1β) were significantly elevated in the IgG group (p&lt;0.05) vs. the untreated group, they were not in the IL-5 mAb group. In this model, all mice treated with CART19 cells were able to clear the tumor burden. However, in a follow-up challenge model generated by engrafting NSG mice with 1x106 luciferase+ JeKo-1 cells, mice treated with a combination of 1x106CART19 cells + IL-5 mAb showed reduced weight loss (p&lt;0.0001) and enhanced overall survival (p&lt;0.01) vs. mice treated with CART19 + IgG. Next, we evaluated IL-5 neutralization in an immunocompetent toxicity model. BALB/c mice were treated with 10×10⁶ murine untransduced T cells, CART19 + IL-5 mAb, or CART19 + IgG (10 mg/kg, weekly). Mice receiving IL-5 mAb exhibited significantly reduced weight loss (p&lt;0.05, Day 1) and lower neuroscore (p&lt;0.05, Days 1, 6, and 8) vs. those receiving IgG control, with a consistent trend observed on other days, supporting a protective role for IL-5 blockade in mitigating CART-associated toxicities. To explore the direct effects of IL-5 on CART19 cells, we disrupted either IL-5 (IL-5KO-CART19) or its receptor (IL-5RαKO-CART19) using CRISPR-Cas9. In NSG mice engrafted with 1×10⁶ luciferase+NALM6 cells, mice receiving 1×10⁶ IL-5KO-CART19 vs. IL-5WT-CART19 showed a trend toward reduced weight loss (p=0.08), significantly increased antitumor activity by Day 20 (p&lt;0.05), and improved overall survival (p&lt;0.05), indicating that IL-5 production can significantly impair CART19 cell efficacy. We next evaluated changes in IL-5Rα gRNA representation in a published genome-wide CRISPR screen (PMID: 39266501). CART19 cells with IL-5Rα-targeting gRNAs were enriched following chronic stimulation, indicating a protective effect for IL-5 pathway interruption. In subsequent studies, IL-5RαKO-CART19 cells showed enhanced killing of JeKo-1 cells following 48 hours of co-culture (p&lt;0.05) and reduced co-expression of multiple inhibitory markers (p&lt;0.01) following chronic stimulation with JeKo-1 cells for one week vs. IL-5RαWT-CART19 cells, suggesting an improvement in CART19 cell activity and phenotype following disruption of IL-5Rα. Conclusion: Our data identify IL-5 as a previously unrecognized mediator of CART–associated toxicities and show significant improvement of CART19 activity with disruption of IL-5 signaling either indirectly with an IL-5 neutralizing antibody or directly with CRISPR gene editing. Thus, IL-5 could serve as a dual-purpose target to improve both safety and efficacy of CART cell therapy.