Evaluation of the inpatient use of inotuzumab ozogamicin and creation of appropriate use guidelines.

Inpatient use of inotuzumab ozogamicin (IO) at our academic medical center has increased since its FDA approval in 2017. Administration of IO does not require hospitalization and is appropriate for outpatient use. The aim of this report is to assess the appropriateness of use, overall inpatient utilization, and cost of IO. This is a retrospective chart review of patients that received at least one dose of IO while admitted to the hospital. Data points included rationale for inpatient IO administration, hospital admission reason, number of IO doses and number of vials used, length of stay, in-hospital mortality, percentage of admissions that were new-starts, outpatient continuation of IO, use of concomitant regimens, and CD22 positivity. Between September 1, 2017, and June 30, 2022, 55 doses of IO were identified. Of the 29 unique admissions, common rationales for inpatient IO use included high disease burden/tumor lysis syndrome risk (31%) and use of a regimen requiring hospitalization (28%). The rationale for hospitalization was most commonly 'chemotherapy administration' (34%) and 'relapsed/refractory disease' (38%). Median length of stay was 23 days, most were new starts (76%), and 5 patients died during the associated admission. Only 63% of patients continued therapy in the outpatient setting. The inpatient use of IO was associated with a prolonged length-of-stay, a 17% in-hospital mortality, and represents a significant cost burden to the health system. As a result of these findings, guidelines for inpatient use of IO were implemented across the health system.