Outpatient Administration of CAR T-cell Therapies Using a Strategy of No Remote Monitoring and Early CRS Intervention

• Commercial CAR T-cell therapies including CARs with CD28 domain may be given safely as outpatient without intense home-monitoring.

• Low-grade cytokine release syndrome can be managed in the outpatient setting with a well-structured system.

Recent studies demonstrating the feasibility of outpatient chimeric antigen receptor modified (CAR) T-cell therapy administration are either restricted to CARs with 41BB costimulatory domains or employ intensive at-home monitoring. We report outcomes of outpatient administration of all commercially available CD19- and BCMA-directed CAR-T therapy using a strategy of no remote at-home monitoring and an early cytokine release syndrome (CRS) intervention strategy. Patients with hematologic malignancies who received CAR T-cell therapy in the outpatient setting during 2022-23 were included. Patients were seen daily in the cancer center day hospital for the first 7-10 days and then twice weekly through day 30. The primary endpoint was to determine 3-, 7- and 30-day post CAR T-cell infusion hospitalizations. Early CRS intervention involved administering tocilizumab as an outpatient for grade ≥1 CRS. 58 patients received outpatient CAR T-cell infusion (33 myeloma, 24 lymphoma and 1 acute lymphoblastic leukemia). Of these, 17 (41%), 16 (38%), and 9 (21%) patients were admitted between days 0-3, 4-7 and 8-30 post-CAR T-cell infusion, respectively. The most common reason for admission was CAR T-cell-related toxicities (33/42). Hospitalization was prevented in 15 out of 35 patients who received tocilizumab for CRS as an outpatient. The non-relapse mortality rates were 1.7% at 1 month and 3.4% at 6 months. In conclusion, we demonstrate that the administration of commercial CAR T-cell therapies in an outpatient setting is safe and feasible without intensive remote monitoring employing an early CRS intervention strategy. -