Hospital admissions and subsequent outcomes from immune-related adverse events.

Abstract

e21590 Background: Checkpoint inhibitor (CPI) use has been increasing in recent years. Immune related adverse events (irAEs) are a known complication of CPIs, particularly with the concurrent use of PD-1 and CTLA-4 inhibitors (combination therapy). IrAEs are associated with increased hospital resource utilisation including admissions and immunomodulator therapy. This is a retrospective analysis of patients receiving CPI therapy for metastatic melanoma. Methods: Data was collected from a Queensland Health centre using electronic medical records and immunotherapy prescribing software. Patient demographics, CPIs, irAEs, admissions, and outcomes were recorded from 2015-2019. All patients had metastatic disease; they either received single agent or combination CPI as first line metastatic treatment or received single agent CPI as adjuvant therapy. Patients admitted to hospitals without electronic medical records were not included. Results: 51 out of 343 patients were eligible for analysis, indicating 15% of patients receiving CPI required hospital admissions due to irAEs. The mean age was 64.7 years, with 64.7% male patients. The commonest BRAF status was wild type (60.8%, n = 31). 54.9% (n = 28) of patients received combination therapy, 39.2% (n = 20) received PD-1 inhibitors, and 5.9% (n = 3) received CTLA-4 inhibitors. 24% (n = 12) of patients experienced early toxicity, defined as hospital admission after one dose. The commonest early toxicity was pneumonitis; all had received PD-1 inhibitors. In the rest of the cohort, the most frequent irAE was colitis (35.3%, n = 18). Regardless of CPI, average length of admission was 6-7 days. 17.6% (n = 9) patients had greater than one admission. Rescue immunomodulators were required in eight patients (15.7%), seven of whom had received combination therapy. Of patients with irAE from combination therapy, 28.7% (n = 8) were palliated due to progressive disease (PD), and 25% (n = 7) continued on single agent PD-1 inhibitor. In patients with irAE from PD-1 inhibitors, the majority (70%, n = 14) ceased treatment; of these, 8 had stable disease and 6 developed PD and were subsequently palliated. Conclusions: IrAEs are a well-documented complication of CPIs. Important considerations for CPI use include severe irAEs requiring admission and subsequent hospital resource utilisation. This occurs not infrequently, as demonstrated in this analysis. It is important to consider individual patient risks and benefits prior to commencement of treatment.