Diagnosis of IA following patient-reported symptoms was an average of 5.2 months, with a significant difference in lag time to diagnosis depending on initial joint presentation. For example, patients with initial small joint involvement had a 10 month longer lag time to IA diagnosis than those with knees as the initial joint involved.
In terms of treatment, 24 patients were treated with systemic corticosteroids and 10 required additional immunosuppression. The need for corticosteroids did not differ by ICI treatment regimen, but those treated with combination therapy were more likely to require additional immunosuppression (P = 0.02).
Tumor necrosis factor inhibitors with or without methotrexate were prescribed for seven patients. All of the patients had a clinical improvement in their arthritis symptoms. Four had a complete tumor response at the time of tumor necrosis factor inhibitor initiation with none having tumor progression.
The three patients treated with methotrexate monotherapy had a complete or sustained partial tumor response to ICI therapy and their cancer did not develop during IA management follow-up.