Outcomes and toxicities of immune checkpoint inhibitors in patients with lung cancer and pre-existing autoimmune disease.

[BACKGROUND] Patients with pre-existing autoimmune disease (PAD) are often excluded from immune checkpoint inhibitor (ICI) clinical trials in thoracic oncology, creating uncertainty regarding their real-world safety and effectiveness in this population.

[PURPOSE] We conducted a retrospective matched cohort study to evaluate clinical outcomes and treatment-related toxicities of ICIs in lung cancer patients with PAD compared to matched controls without PAD.

[PROCEDURES] Using the provincial IMPACT-MB database, lung cancer patients with PAD were matched to controls by age and sex. Demographic, disease, and treatment data were extracted from medical records. Primary outcomes included toxicity, time to treatment failure (TTF), overall survival (OS), and objective response rate (ORR). Associations were determined using Cox and logistic regression modeling.

[MAIN FINDINGS] Of 1871 ICI-treated patients, 69 with PAD were identified and matched to 139 controls. Rates of immune-related adverse events were similar between PAD and control groups (45% vs. 38%, P = 0.4, OR 1.29, 95% CI 0.72-2.32). In the PAD group, 20% experienced a disease flare. PAD was associated with more frequent ICI treatment holds and initiation of biologic therapy. No significant association was observed between PAD status and OS (HR 0.92, 95% CI 0.65-1.30, p = 0.63) or TTF (HR 0.75, 95% CI 0.54-1.05, p = 0.09).

[CONCLUSIONS] In this real-world retrospective matched cohort study, PAD was not associated with increased toxicity or inferior oncologic outcomes. One in five patients with PAD experienced autoimmune flare, underscoring the need for close monitoring. These findings support ICI use in carefully selected lung cancer patients with PAD.