Immune Checkpoint Inhibitors Did Not Exacerbate Autoimmune Rheumatic Disease Activity in Patients With Cancer

BACKGROUND: The safety of immune checkpoint inhibitors (ICIs) in patients with cancer and preexisting or acquired autoimmune rheumatic diseases (ARDs) remains unclear. This study aimed to evaluate the safety of ICIs in patients with cancer and preexisting or acquired ARDs using a relatively large real-world database. PATIENTS AND METHODS: Using the Chang Gung Research Database, we identified 23,981 patients with cancer who received either ICIs or other systemic anticancer treatments between January 1, 2002, and March 31, 2022. After propensity-score matching at a 1:2:4 ratio based on age, sex, and cancer type, we established 3 groups for analysis: group 1 (patients with both cancer and ARDs who received ICI therapy [Cancer+ICI+ARD+]; n=303), group 2 (patients with cancer without ARDs who received ICI therapy [Cancer+ICI+ARD-]; n=597), and group 3 (patients with cancer with ARDs who received systemic anticancer therapy without ICIs [Cancer+ICI-ARD+]; n=1,212). The Wilcoxon signed-rank test and McNemar's test were used to assess changes in steroid and disease-modifying antirheumatic drug (DMARD) dosages, as well as laboratory parameters associated with ARD activity, before and after ICIs. RESULTS: The study found no significant differences between patients with cancer treated with ICIs who did or did not have ARDs, particularly with respect to steroid dosage. DMARD dosages did not increase after ICI treatment, regardless of ARD status. Laboratory parameters related to ARD activity also showed no significant changes before and after ICI therapy. Notably, immune-related adverse events-aside from an increased incidence of skin complications such as psoriasis (2.31% in group 1 vs 0.41% in group 3; P