Rheumatic and Musculoskeletal Immune-Related Adverse Events Due to Immune Checkpoint Inhibitors: A Systematic Review of the Literature

Objective: Immune checkpoint inhibitors (ICIs) are improving prognoses in advanced stage cancers, but they also lead to immune-related adverse events (IRAEs). IRAEs targeting many organ systems have been reported, but musculoskeletal and rheumatic IRAEs have not been well-characterized. We systematically reviewed published literature on musculoskeletal and rheumatic IRAEs to better understand prevalence and clinical characteristics. Methods: Medline and CENTRAL databases were searched for articles reporting rheumatic and musculoskeletal IRAEs secondary to ICI treatment. After screening abstracts and full texts in duplicate, clinical features, prevalence, and treatment data were extracted and summarized. Results: A total of 1,725 unique abstracts were screened; 231 contained original data and were about ICIs and went to full-text screening. Fifty-two of these contained information about musculoskeletal or rheumatic IRAEs or about treatment with ICIs in preexisting autoimmune disease. Of these, 33 were clinical trials, 3 were observational studies, and 16 were case reports or series. Arthralgia prevalence in clinical trials ranged 1–43%, and myalgia was reported in 2–20%. Arthritis was reported in 5 of 33 clinical trials, and vasculitis was reported in only 2. One observational study and 3 case reports described patients with preexisting autoimmune disease treated with ICIs. Case reports included development of inflammatory arthritis, vasculitis, myositis, and lupus nephritis. Conclusion: Arthralgia and myalgia have been reported commonly in patients treated with ICIs. The prevalence of rheumatic IRAEs such as inflammatory arthritis, vasculitis, and sicca syndrome is less clear from current evidence. There is limited observational and case-level evidence describing ICI use in patients with preexisting autoimmune disease.