National burden and outcomes of CAR-T therapy toxicities in DLBCL, multiple myeloma, and B-ALL: A retrospective analysis of the Nationwide Inpatient Sample.

e19108 Background: Chimeric antigen receptor (CAR) T-cell therapy achieves durable responses in diffuse large B-cell lymphoma (DLBCL), multiple myeloma (MM), and B-cell acute lymphoblastic leukemia (B-ALL). However, toxicities including cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) complicate care and strain resources. Population-based estimates of toxicity rates across indications remain limited. We performed a national retrospective analysis to compare toxicity incidence and burden, aiming to inform risk stratification and resource planning. Methods: Using the Nationwide Inpatient Sample (NIS) 2020–2022, we identified adult hospitalizations receiving CAR-T for DLBCL, MM, or B-ALL (ICD-10 codes). We collected sociogeographic data, inpatient outcomes (mortality, length of stay LOS, total charges), and complications including CRS, ICANS, sepsis, acute renal failure (ARF), and others. Analyses used Stata 18. 5 with survey weighting. Multivariable logistic regression evaluated associations between indication and outcomes. p<0. 05 was significant. Results: Among 10, 650 CAR-T recipients, DLBCL (46. 5%) and MM (19. 6%) cohorts were older (mean age 62. 7 and 63. 6 years), whereas B-ALL (10. 9%) patients were younger (mean 26 years). Median LOS was longest in B-ALL (19. 2 days), followed by DLBCL (16. 9) and MM (13. 5; p<0. 0001). Mean hospital charges were highest in DLBCL (1, 346, 614), exceeding MM (973, 800) and B-ALL (973, 134; p<0. 0001). Inpatient mortality was similar: MM 3. 8%, B-ALL 3. 0%, DLBCL 2. 8% (p=0. 61). CRS occurred in 47. 1% overall, highest in MM (53. 96%), then DLBCL (46. 91%) and B-ALL (35. 62%; p<0. 001). On multivariable analysis, MM had higher odds of CRS vs. DLBCL (OR 1. 33; 95%CI 1. 05–1. 67; p=0. 016), while B-ALL had lower odds (OR 0. 63; 95%CI 0. 47–0. 84; p=0. 002). ICANS occurred in 14. 7% overall, most in DLBCL (16. 41%), then B-ALL (13. 73%), and least in MM (11. 03%; p=0. 03). MM had lower odds vs. DLBCL (OR 0. 63; 95%CI 0. 45–0. 90; p=0. 01). Any complication was common across groups (MM 67. 4%, DLBCL 66. 0%, B-ALL 56. 2%; p=0. 01) ; B-ALL had lower adjusted odds vs. DLBCL (OR 0. 66; 95%CI 0. 50–0. 89; p=0. 006). ARF was most frequent in MM (21. 6% vs. DLBCL 13. 9%, B-ALL 9. 4%; p<0. 0001), with higher odds vs. DLBCL (OR 1. 71; 95%CI 1. 27–2. 29; p=0. 000). Rates of sepsis, mechanical ventilation, and vasopressor use did not differ significantly by indication. Conclusions: In this national cohort, CAR-T toxicities are common and confer substantial clinical and economic burden. DLBCL carries the highest costs; MM is associated with increased CRS and ARF but lower ICANS vs. DLBCL; and B-ALL, despite younger age and fewer complications, has the longest hospitalizations. These data support indication-specific toxicity mitigation, risk stratification, and resource planning as CAR-T use expands.