Survival in immune checkpoint inhibitor-treated patients with rheumatoid arthritis and non-small cell lung cancer: an observational cohort study.

Objective: To compare overall survival (OS) in immune checkpoint inhibitor (ICI)-treated patients with metastatic non-small cell lung cancer (mNSCLC) with pre-existing RA versus those without RA.

Methods: A retrospective cohort study using Medicare Claims data was performed. Participants included patients ≥ 66 years of age with a diagnosis of a malignant neoplasm of lung and bronchus (who initiated nivolumab, pembrolizumab, or atezolizumab between 3/4/2015-4/11/2019, which is after FDA approval of ICIs for mNSCLC but prior to first FDA approval for stage III disease. Survival analysis using Kaplan Meier and adjusted Cox Proportional Hazard models was performed.

Results: A total of 2,732 people with mNSCLC (N=790 RA and N=1942 non-RA) were in the analytic cohort. RA patients were more likely to be female and had more comorbidities, than non-RA patients. RA patients were more likely to be taking steroids than non-RA patients (63% vs 45%), but equally likely to be taking dexamethasone, usually prescribed for cancer palliation, specifically (27% vs 28%) prior to ICI initiation. There was no difference in overall survival (OS) between the RA and non-RA NSCLC Kaplan Meier survival curves (log-rank p-value=0.08) and in adjusted models, (Hazard Ratio 0.92 [0.78, 1.09]). Male sex, having more comorbidities, and steroid dose prior to ICI initiation were associated with worse OS. In a sensitivity analysis omitting patients on baseline dexamethasone, steroid dose prior to ICI initiation was no longer associated with worse OS.

Conclusion: After controlling for demographics and comorbid conditions, ICI-treated RA patients with mNSCLC had no difference in OS compared to non-RA patients. After excluding patients on dexamethasone, steroid dose was not associated with worse OS.