Real‐world experience of immune checkpoint inhibitors in patients with solid tumours in the Top End of the Northern Territory, Australia from 2016 to 2021: a retrospective observational cohort study

Background Use of immune checkpoint inhibitors is growing, but clinical trial data may not apply to Indigenous patients or patients living in remote areas. Aims To provide real‐world incidence of immune‐related adverse events (irAE) in the Top End of the Northern Territory and compare incidence between demographic subgroups. Methods This retrospective, observational, cohort study collected data from electronic records of patients living in the Top End with solid organ cancer treated with immunotherapy between January 2016 and December 2021. The primary outcome was cumulative incidence of any‐grade and severe irAE. Secondary outcomes were overall survival, treatment duration and reason for treatment discontinuation. Results Two hundred and twenty‐six patients received immunotherapy. Forty‐eight (21%) lived in a remote or very remote area, and 36 (16%) were Indigenous. Cumulative incidence of any‐grade irAE was 54% (122/226 patients); incidence of severe irAE was 26% (59/226 patients). Rates were similar between Indigenous and non‐Indigenous patients of any‐grade (42% vs 56%, P = 0.11) and severe (11% vs 18%, P = 0.29) irAE. However, Indigenous patients had shorter treatment duration, more frequently discontinued treatment due to patient preference and appeared to have shorter median overall survival than non‐Indigenous patients (17.1 vs 30.4 months; hazard ratio (HR) = 1.5, 95% confidence interval (CI) = 0.92–2.66). There was no difference in mortality between remote and urban patients (median overall survival 27.5 vs 30.2 months; HR = 1.1, 95% CI = 0.7–1.7). Conclusions Rates of irAE in our cohort are comparable to those in the published literature. There was no significant difference in any‐grade or severe irAE incidence observed between Indigenous and non‐Indigenous patients.