Characteristics of hospital admission during checkpoint-inhibition therapy.

e14510 Background: Immune checkpoint inhibitors (ICI) have enriched the therapeutic armamentarium in outpatient oncology care; however, data on necessity of hospitalizations associated with immune-related adverse event (irAEs) are scarce. Here, we retrospectively characterize hospitalizations of patients (pts) undergoing ICI. Methods: Between 12/2019 and 06/2022, 237 pts were included. Clinical data and characteristics of ICI were collected during a 6-month observation period after the initiation of therapy. Descriptive Statistics and Kaplan-Meier statistics were administered. Results: 30 out of 237 pts were hospitalized (HA+). Most common underlying tumor entities in the overall cohort were malignant melanoma (59.5%), renal cell carcinoma (13.1%), and non-small cell lung carcinoma (12.7%). Hospitalized pts exhibited an increased rate of pulmonary and cerebral metastases. We observed a significantly higher hospitalization rate during dual ICI with Nivolumab and Ipilimumab. The predominant irAEs for hospitalization were colitis (26.7), followed by hypophysitis (13.3%), leading to a median hospitalization of 7 days (range 1-34). Most pts were treated on the general ward (76.7%). Interdisciplinary consultations were frequent, especially to gastroenterology (46.7%) and neurology (26.7%). Although a trend towards an overall survival in the HA+ subgroup was identified, no statistically significant difference was found among the subgroups. Conclusions: The hospitalization rate of 12.6% is comparable to the literature. There was a disproportionate admission of patients with immune-related colitis and hypophysitis compared to the prevalence described under ICI. We observed a high need for interdisciplinary consults in line with the heterogeneity of immune-mediated side effects. When compared to non-hospitalized pts, there was no survival disadvantage in the cohort of hospitalized patients.