11168 Background: Immune checkpoint inhibitors (ICIs) improve outcomes across multiple malignancies but are associated with immune-related adverse events (irAEs). Patients with rheumatoid arthritis (RA) have been largely excluded from clinical trials, and disease-specific real-world data remain limited. We evaluated irAEs and survival outcomes in cancer patients with and without preexisting RA treated with ICIs. Methods: We conducted a retrospective cohort study using the TriNetX Research Network. Patients with RA diagnosed prior to ICI initiation were compared with patients without RA. Propensity score matching (1:1) was performed on age, sex, race, ethnicity, cancer type, ICI type, comorbidities, metastatic disease, other autoimmune conditions, and preexisting irAE codes. Outcomes were measured beginning 1 day after ICI initiation. Overall survival (OS) and organ-specific irAEs were assessed. Sensitivity analyses were conducted excluding patients with baseline glucocorticoid or disease-modifying antirheumatic drug (DMARD) exposure to account for differences in preexisting autoimmune treatment. Results: Before matching, 3,172 patients with RA and 156,543 without RA were identified. After matching, 3,162 patients were included in each cohort with balanced baseline characteristics and laboratory values. OS was numerically lower in the RA cohort but not statistically significant (29% vs 30%; median 21.9 vs 23.7 months; p = 0.1861). Early survival differed within 6 months (76% vs 78%; p = 0.0415) but not at 1 year. RA patients experienced higher rates of gastrointestinal (8.4% vs 6.9%; p = 0.0234) and pulmonary irAEs (5.4% vs 4.0%; p = 0.0106), with no significant differences in hepatic, dermatologic, or endocrine irAEs. Glucocorticoid and DMARD use were more frequent in RA patients. In sensitivity analyses excluding prior exposure, new DMARD use remained significantly higher in RA patients (4.5% vs 1.0%; p < 0.0001), while other differences attenuated. Conclusions: Cancer patients with preexisting RA treated with ICIs experience higher rates of select irAEs without a significant long-term OS disadvantage. These findings suggest increased immune toxicity risk with preserved anticancer efficacy, supporting cautious but feasible ICI use in RA patients with appropriate monitoring.
Aibani et al. (Wed,) studied this question.