Abstract

e23320 Background: A significant portion of cancer patients are treated with immune checkpoint inhibitors (ICI) and many experience immune related adverse events (irAE) which impact treatment and outcomes. A paucity of data exists related to use of ICIs in Early Onset Cancers (EOC), their irAE, and its correlation to outcomes. Methods: A single institution database of immunotherapy use from an NCI-designated cancer center (NCI-CC) was reviewed with patients treated from 2010-2019. Two cohorts were examined: EOC (age ≤50 at diagnosis), and age > 50. Clinically significant irAEs were defined as those requiring hospitalization (≥grade 3). Pearson's Chi-squared test and Fisher's exact test were used for analysis. Significance was defined as p < 0.05. Results: A total of 1067 patients were identified, 173 were EOC. Race and ethnicity were similar between groups, the EOC group had significantly higher proportion of females, private insurance, working, single, treated at main campus, and ECOG 0. Main cancer types in EOCs were skin cancers (38.2%), lung (16.2%), and heme malignancies (11.6%); those > 50 were lung (46.6%), skin cancer (21.6%), and GU malignancies (11.2%). Stages of cancer were not statistically different nor was type or doses of ICI. EOCs were more likely to get a greater number of ICIs. IrAE requiring hospitalization were similar between groups; 20 (11.6%) in EOC vs 95 (10.6%) in > 50. There was no difference in the incidence of specific irAEs. Further stratification of EOC cohort by age group 13-30, 31-40, and 41-50 demonstrated no difference in experience of an irAE. Ipilimumab had the highest incidence of irAE in EOC; 12 (75.0%) vs 52 (33.1%), as did receiving 2+ ICIs: 11 (68.8%). The number of doses of a specific ICI was not correlated to irAE in EOC. EOC patients without an irAE were more likely to have a disease response; either stable disease, partial response, or a complete response: 21 (70.0%) vs 1 (12.5%); there was no difference in mortality. Conclusions: In a single NCI-CC review of ICI use, EOC had no difference in ≥grade 3 irAEs or in specific irAEs relative to older adults. Within EOCs, those who experienced a significant irAE were more likely to have received Ipilimumab or 2+ ICIs and were less likely to obtain a response to treatment, although mortality was not different. [Table: see text]