Outcomes of Immune Checkpoint Inhibitor Administration in Hospitalized Patients With Solid Tumor Malignancies.

Purpose: More oncologists desire to treat their patients with immune checkpoint inhibitors (ICIs) in the inpatient setting as their use has become more widespread for numerous oncologic indications. This is cost-prohibitive to patients and institutions because of high drug cost and lack of reimbursement in the inpatient setting. We sought to examine current practice of inpatient ICI administration to determine if and in which clinical scenarios it may provide significant clinical benefit and therefore be warranted regardless of cost.

Methods: We conducted a retrospective chart review of adult patients who received at least one dose of an ICI for treatment of an active solid tumor malignancy during hospitalization at a single academic medical center between January 2017 and June 2018. Patient, disease, and admission characteristics including mortality data were examined, and cost analysis was performed.

Results: Sixty-five doses of ICIs were administered to 58 patients during the study period. Nearly 40% and 80% of patients died within 30 days and 180 days of ICI administration, respectively. There was a trend toward longer overall survival in patients with good prognostic factors including positive programmed death-ligand 1 (PD-L1) expression or microsatellite instability-high (MSI-H) status. Slightly over 70% of patients were discharged within 7 days of ICI administration. The total cost of inpatient ICI administration over the 18-month study period was $615,016 US dollars.

Conclusion: Inpatient ICI administration is associated with high costs and poor outcomes in acutely ill hospitalized patients with advanced solid tumor malignancies and therefore should largely be avoided. Careful discharge planning to expedite outpatient treatment after discharge will be paramount in ensuring patients with good prognostic features who will benefit most from ICI therapy can be promptly treated in the outpatient setting as treating very close to discharge in the inpatient setting appears to be unnecessary, regardless of tumor features.