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 2: Preexisting Systemic Autoimmune Rheumatic Diseases.

OBJECTIVE Although immune checkpoint inhibitors (ICIs) are increasingly used in patients with preexisting systemic autoimmune rheumatic diseases (SARDs), a key concern is whether baseline immunosuppression at the start of ICI treatment might negatively affect cancer outcomes. This risk must be carefully weighed against the potential for a SARD flare. The objective of this study was to develop a living guideline that will provide up-to-date guidance on the management of baseline immunosuppression for preexisting SARDs 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 SARDs. RESULTS We identified 67 publications that reported on immunosuppression and cancer outcomes by specific preexisting rheumatic diseases, including 36 on preexisting SARD. 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 SARD flare, risk of organ- or life-threatening manifestations, and potential effect of immunosuppression on cancer outcomes. Seven specific recommendations were made, 1 each for preexisting systemic lupus erythematosus, systemic sclerosis, Sjögren disease, myositis, sarcoidosis, vasculitis, and Behçet disease, considering both the available evidence and expert consensus. The general recommendation for preexisting SARDs was to continue baseline immunosuppression, particularly if there are organ- or life-threatening manifestations. CONCLUSION This living guideline will provide contemporary baseline immunosuppression recommendations for individuals with cancer and preexisting SARDs 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).