The researchers noted that treating patients with ICI-induced IA is complicated by a history of active or recently treated cancer and concerns over using immunosuppression in the context of ICI therapy.
They set out to evaluate the clinical presentations of 30 patients seen in their clinic with ICI-induced IA. Patients were a median of 59 years old and 12 (40%) were female. Tumor types included metastatic melanoma, non–small cell lung cancer, small cell lung cancer, colorectal cancer, Hodgkin lymphoma, cutaneous lymphoma, renal cell carcinoma, duodenal carcinoma, Merkel cell carcinoma, cutaneous basal cell carcinoma, and cutaneous squamous cell carcinoma.
Sixteen patients were treated with anti–programmed cell death protein 1 (PD-1)/programmed death ligand 1 monotherapy, and 14 were treated with combination anti–CTLA-4/PD-1 therapy.
Patients on combination therapy were significantly younger (7.5 years, P = 0.01) and were more likely to have metastatic melanoma as their underlying cancer.
Patients who received combination therapy were more likely to present first with knee IA (n = 10) and none had small joint involvement. In contrast, initial small joint involvement was more common in the monotherapy group (n = 6).