Background: The engineered T-cell products axicabtagene ciloleucel (axi-cel) and brexucabtagene autoleucel (brexu-cel) are FDA approved for relapsed/refractory diffuse large B-cell lymphoma (DLBCL) and mantle cell lymphoma (MCL), respectively. This study investigated real-world rates of CRS and ICANS following CAR-T. Methods: This study analyzed CIBMTR data of US SUBJ receiving axi-cel or brexu-cel for any indication from Oct 2020–Dec 2021 with ≥1 follow-up visit. CRS and ICANS were graded per American Society for Transplantation and Cellular Therapy consensus guidelines. Results: 927 SUBJ (median age, 63 y; men, 65%) from 87 centers were analyzed. Most received axi-cel (76%), 83% of whom had DLBCL or transformed follicular lymphoma (tFL); 24% received brexu-cel (MCL). Most SUBJ had Ann Arbor stage III/IV (63%), no active central nervous system disease (84%), and refractory disease at CAR-T infusion (66%). Among all 589 SUBJ with DLBCL/tFL who received axi-cel, 54% achieved complete response, 17% partial response, and 6% stable disease. 89/715 SUBJ with available data received treatment for CRS prevention, mostly tocilizumab alone (80% [71/89]) or in combination (3% [3/89]). Overall, 766 SUBJ (83%) developed CRS (grade ≥3, 64 [8%]; Table). Of the 89 SUBJ who received CRS prevention treatment, 78% developed CRS, with 3% (3/89) having grade ≥3. 77% of SUBJ with CRS received CRS treatment, 97% of whom received tocilizumab (alone or in combination [eg, with corticosteroids]). Most (64%) SUBJ with grade 1 CRS received treatment, 63% of whom received tocilizumab alone. ICANS occurred in 424/876 SUBJ with ICANS data (48%; Table), of whom 205 (48%) had grade ≥3. ICANS treatment was reported and administered to 86% of SUBJ with ICANS, 92% of whom received corticosteroids. Conclusions: CRS and ICANS incidence rates were consistent with previously published literature and highlight potential burdens of CAR-T. In addition, the treatment landscape for CRS is changing; SUBJ with grade 1 CRS often received treatment. These data will inform the design of future studies aimed at preventing and treating CAR-T toxicities.

All SUBJ with data available for *CRS or ^†ICANS.