Mortality in US Veterans with Rheumatoid Arthritis Treated with Immune Checkpoint Inhibitors (ICIs)

Objective : This investigation compared all‐cause and cause‐specific mortality in patients with and without rheumatoid arthritis (RA) in the Veterans Health Administration (VHA) following immune checkpoint inhibitor (ICI) cancer treatment. Methods : Veterans with RA and a control set of Veterans without RA matched on age, sex and year of VA enrollment who had received an ICI were identified. All‐cause and cause‐specific mortality were obtained. Survival from the time of ICI initiation was evaluated using Cox models, Kaplan‐Meier curves. and log rank testing. Results : There were 301 RA patients and 2,114 non‐RA controls treated with an ICI. The majority of RA and non‐RA patients were white, male, and current/former smokers. Lung cancer was the most common malignancy (51.2%), pembrolizumab was the most frequently used ICI (43.9%), and most patients received ICI monotherapy (97.1%). Cox proportional hazard ratio comparison of all‐cause mortality in RA patients to non‐RA controls was 1.08 (0.94, 1.25, 95% CI) for the crude analysis and 1.09 (0.94, 1.25, 95% CI) for the adjusted analysis. Cause of death was similar in the two groups, most frequently neoplasm in 93.0% and 90.9% for RA and non‐RA groups, respectively (p=0.737). Deaths due to infection were rare in both groups (<1.0%). Conclusion : Patients with RA who received ICIs for the treatment of malignancy did not experience increased mortality or differences in cause of death compared to patients without RA receiving ICIs. These preliminary data suggest ICI therapy may be considered as part of cancer treatment in RA patients based on individual patient circumstances.