Outpatient administration of CAR T-cell therapy: A University of Arizona Cancer Center experience.

e23167 Background: Chimeric antigen receptor T-cell (CAR T) therapy has traditionally been administered in an inpatient setting. This approach is associated with significant healthcare costs and risks, including extended hospital stays, nosocomial infections, physical deconditioning, and psychological distress (1). Evidence supports the feasibility of administering CAR T-cell therapy in the outpatient setting, offering an alternative with potentially improved outcomes and reduced costs. Methods to implement this in an outpatient setting have included early CRS (cytokine release syndrome) intervention with tocilizumab and multidisciplinary support including patient access to healthcare providers 24 hours a day (2-4). Methods: At the University of Arizona Cancer Center, we have developed an outpatient program for the administration of CAR T-cell therapy, including daily monitoring of patients in the clinic and direct admission to a dedicated CAR T bed for toxicities. A retrospective chart review was conducted of patients who received outpatient, commercially available CAR T-cell therapy at the University of Arizona Cancer Center between December 2018 and November 2024. Results: Thirty-nine (out of 91 total) patients underwent outpatient CAR T-cell therapy for diffuse large B-cell lymphoma (n = 28), multiple myeloma (n = 8), follicular lymphoma (n = 2), and plasma cell leukemia (n = 1). CAR T-cell products administered included axicabtagene ciloleucel (n = 2, 5.1%), tisagenlecleucel (n = 28, 71.8%), and ciltacabtagene autoleucel (n = 9, 23.1%). Among these, 77% (30) required hospitalization, most commonly due to CRS (67%, n = 20), mental status changes (27%, n = 8), hypotension (23%, n = 7), tachycardia (13%, n = 4), suspected or confirmed infection (7%, n = 2), and hypoxia (3%, n = 1). The mean hospital length of stay (LOS) was 2.7 days. Of those hospitalized, 20% (6) required ICU care with a mean LOS of 4.5 days. In comparison, CAR T given inpatient was associated with an average hospital LOS of 17.9 days (n = 52). CRS occurred in 69% (27) of patients, predominantly grade 1 (63%, n = 17), with 1 case of grade III and no cases of grade 4. Of these patients, 20 (74%) were treated with tocilizumab, all of which were administered inpatient. The mean time to CRS onset was 3.7 days. Immune effector cell-associated neurotoxicity syndrome (ICANS) was observed in 33% (13) of patients, with 38% (5) experiencing grade III or IV symptoms. Among these, 62% (8) were treated with steroids, and 23% (3) received Anakinra. The mean time to ICANS onset was 6.5 days. 38% (15) of patients achieved a complete response (CR) and partial responses (PR) were observed in 33% (13) of patients. Overall mortality was 36% (14), with disease progression being the leading cause of death (57%, n = 8). Conclusions: Our study shows CAR T-cell therapy can be safely administered in the outpatient setting with close monitoring, reducing inpatient LOS significantly.