Immune Checkpoint Inhibitor-Induced Inflammatory Arthritis: Overview of Therapies and a Personalized Approach to Optimized Combined Therapy.

Immune checkpoint inhibitors (ICIs), including anti-cytotoxic T lymphocyte antigen 4, anti-programmed cell death 1, and anti-programmed cell death ligand 1 (PD-L1) antibodies, are currently widely used in oncology clinical practice, achieving considerable success in improving disease outcomes. New checkpoint targets are being discovered and investigated through basic science research and clinical trials. ICI remove negative regulatory immune signals on T cells, leading to immune activation and induction of antitumor immunity. Patients who receive ICI, however, are at risk for developing immune-related adverse events (irAEs), which are attributed to increased T cell activity against antigens in both tumors and in healthy tissues, to increased inflammatory cytokine levels, to increased levels of preexisting autoantibodies, and to enhanced complement-mediated inflammation. Arthritis is one of the most common irAEs. ICI-induced rheumatic irAEs are categorized by levels of severity which guide the choice of treatment options. Management of ICI-induced rheumatic irAEs includes the use of glucocorticoids, disease-modifying antirheumatic drugs (mainly methotrexate), and biological agents (e.g., tumor necrosis factor, interleukin-6 receptor, and CD20 inhibitors). This review aims to summarize the current ICI subtypes, their role in rheumatic irAEs development, and therapies currently used in clinical practice to manage irAEs. In addition, we propose to use an ex vivo personalized diagnostic assay for the selection of the most effective ICI with antirheumatic drugs combinations that will inhibit the advancement of ICI-induced adverse events.