Blinatumomab administration in the outpatient setting: Safety and health care utilization

Blinatumomab, a bispecific CD19 × CD3 antibody is effective for the treatment of B-cell acute lymphoblastic leukemia (ALL). Because of its immune toxicities, namely cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), the US Food and Drug Administration (FDA) recommends preemptive hospitalization for the initiation of cycle 1 (C1) and cycle 2 (C2). The necessity of this approach is unclear.

The authors conducted a retrospective cohort study among all patients treated with blinatumomab between 2012 and 2025 at two academic cancer centers: Memorial Sloan Kettering Cancer Center (MSK) and Dana-Farber Cancer Institute (DFCI).

For C1, only nine of 308 (3%) patients initiated outpatient (OP) treatment. A total of 184 of 308 (60%) initiated C2: At DFCI, 10 of 83 (12%) initiated C2 OP and at MSK, and 74 of 101 (88%) initiated C2 OP. Demographic and clinical characteristics were similar between patients initiating C2 inpatient versus OP. No patients who initiated C2 (0 of 184) had Gr3+ CRS (across all cycles) and only two (1%) had Gr3+ ICANS; both were inpatient for C2. Of 84 patients treated without preemptive hospitalization for C2, 16 of 84 (19%) required hospitalization at some point during the cycle, largely for infections (50%).

OP administration of C2 of blinatumomab can be administered safely with no unexpected, severe, or life-threatening toxicities. The ability to safely manage treatment without preemptive hospitalization may support the patient experience and limit costs of care.