Canadian Rheumatology Association/Canadian Research Group of Rheumatology in Immuno-Oncology Living Guidelines for Baseline Immunosuppression in Individuals With Preexisting Rheumatic Diseases Initiating Immune Checkpoint Inhibitors. Part 1: Preexisting Inflammatory Arthritides.

OBJECTIVE Immune checkpoint inhibitors (ICIs) are being increasingly used in patients with preexisting inflammatory arthritides (IAs). However, there are concerns that concomitant baseline immunosuppression at the time of ICI initiation may worsen cancer outcomes, a risk that needs to be balanced with the risk of IA flare. The objective of this study was to develop a living guideline that will offer up-to-date guidance on the management of baseline immunosuppression for preexisting IAs when initiating cancer immunotherapy with ICIs. METHODS The Canadian Research Group of Rheumatology in Immuno-Oncology (CanRIO) formed a multidisciplinary panel composed of rheumatologists, oncologists, researchers, and a patient representative, with methodological support from the Canadian Rheumatology Association (CRA). We completed a systematic literature review to inform this first installment of our living guideline. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, the panel developed recommendations for the management of baseline immunosuppression in individuals with preexisting IAs. RESULTS We identified 67 relevant publications that reported on immunosuppression and cancer outcomes by specific preexisting rheumatic diseases, including 44 on preexisting IA. Eight best practice statements were developed, highlighting the importance of shared decision making between patients and their care team and careful consideration of risk of IA flare, risk of organ- or life-threatening manifestations, and the potential effect of immunosuppression on cancer outcomes. Four specific recommendations were made, one each for preexisting rheumatoid arthritis, polymyalgia rheumatica, psoriatic arthritis, and spondyloarthritis, considering both the available evidence and expert consensus. The general recommendation for preexisting IAs was to reduce or stop baseline immunosuppression, unless there are extraarticular organ- or life-threatening manifestations. CONCLUSION This living guideline will provide contemporary baseline immunosuppression recommendations for individuals with cancer and preexisting IA when initiating ICI therapy. New recommendations will be added over time and updated, with the latest recommendations, evidence summaries, and Evidence to Decision summaries available through the CRA and CanRIO websites (www.rheum.ca, www.canrio.ca). (PROSPERO registration: CRD42023461024).