OUP accepted manuscript

Although indications for immune checkpoint inhibitors (ICIs) have dramatically increased in the past decade, ICIs have been associated with autoinflammatory immune-related adverse events which can resemble autoimmune diseases (ADs). Little is known about the impact of baseline AD on mortality in cancer patients treated with ICIs. Here, we identified 17,497 patients with pre-existing autoimmune diagnoses prior to treatment with anti-PD-1 or anti-PD-L1 therapy and 17,497 matched controls through the TriNetX Diamond network of over 200 million patients across the US and Europe. Using a Cox proportional hazards model, we found that patients with history of AD were not at higher risk of mortality than non-AD controls (HR, 1.03; 95% CI, 1-1.07; p = 0.05). Additionally, history of Hashimoto's disease (HR, 0.75; 95% CI, 0.62-0.90; p = 0.002) and vitiligo (HR,0.52; 95% CI, 0.34-0.81; p = 0.003) were statistically significantly associated with decreased mortality. This suggests that underlying AD need not be a contraindication to inclusion in clinical trials and administration of ICI for treatment of cancer.