C-reactive protein levels were significantly higher in the combination therapy group (4mg/dL vs. 0.5mg/dL, P = 0.03). Only monotherapy patients were positive for anti–citrullinated peptide antibodies, rheumatoid factor, or antinuclear antibodies.
Most of the patients in the study had an additional IrAE, with colitis being the most common (n=10), followed by thyroid disease, pneumonitis, and rash. Patients on PD-1 or programmed death ligand 1 monotherapy were more likely to have IA as their first IrAE.
The research team noted that the median time to symptom onset was 5 months after ICI initiation.