Adverse events during chimeric antigen receptor T-cell (CAR-T) therapy for hematologic malignancies (HM): Real-world, US patient experience

e18891 Background: CAR-T therapy represents the most significant advancement in the treatment of HM in the past 5 years. Life-threatening complications such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) may occur leading to significant morbidity and mortality. We aimed to describes the frequency of CRS and ICANS and the time to onset of each post CAR-T therapy administration in real-world, U.S. patients. Methods: Patients (pts) with HM who received any FDA-approved CAR-T therapy were identified from a U.S. EMR database containing de-identified healthcare data for > 40M patients from > 500 hospitals and 30 healthcare systems (including academic centers). Confirmation of CAR-t treatment was based on ≥1 procedure code for general administration of CAR-T therapy (e.g., XW033C3, introduction of engineered autologous chimeric antigen receptor t-cell immunotherapy into peripheral vein) or a specific approved CAR-T (I.e., XW033K7, introduction of idecabtagene vicleucel immunotherapy into peripheral vein) between 2017 and 2022. Diagnosis of CRS or any ICAN was based ≥1 related ICD-10 diagnosis code (e.g., CRS = D89.83X). Frequency of occurrence of CRS, symptoms of CRS, ICANS symptoms, and severity of CRS or ICANS is described (severity based on validated clinical algorithm). Time to CRS and ICANS was calculated as the interval from CAR-T administration to first reported diagnosis, respectively. Results: 212 pts met the study criteria including 77 b-cell lymphoma, 64 multiple myeloma, 47 follicular lymphoma, 13 mantle cell lymphoma and 11 acute lymphoblastic leukemia pts. The majority were male (54.7%); median age was 60 years. Overall, 100 (47.2%) pts were diagnosed with CRS (any grade) while 82 (38.7%) pts experienced any ICAN symptoms. The top three CRS symptoms were fever (57.5%), hypotension (31.1%) and tachycardia (21.2%). The top three ICANS symptoms were obtundation (18.4%), confusion (12.7%), and delirium (12.7%). Of CRS pts, 25.0% experienced severe symptoms, including renal insufficiency (10.0%), atrial fibrillation (9.0%), ventricular tachycardia (7.0%), and cardiac failure (2.0%). The median time to development of CRS was 2 days (range 0-23 days). Of pts. experiencing ICANS, 72.0% experienced any mild symptom and 53.7% experienced any severe symptom, including obtundation (47.6%), aphasia (13.4%), and seizures (1.2%). The median time to development of ICANS post CAR-T therapy was 6 days (range 0-26 days). Conclusions: Our study is the first real-world, U.S. evaluation of the frequency and time to toxicities associated with CAR-t therapy across multiple hematologic malignancies. While well-described in RCTs these data highlight the need for the continued development of clinical and therapeutic approaches to minimize their impact on the effectiveness of CAR-T.