Rheumatological Immune-related Adverse Events of Checkpoints Inhibitors: a Narrative Review for the Latin American Rheumatologist.

Abstract Latin America is experiencing a demographic and epidemiological transition, with an increase in non-communicable diseases such as cancer. One of the greatest advances in the therapeutic approach to cancer has been the discovery of immunotherapy, and specifically of checkpoint inhibitors (CPIs). Since inhibition of CTLA-4 and PD-1/PD-L1 enhances the immune response, cancer immunotherapies are associated with a new class of toxicities of autoimmune and/or autoinflammatory origin. These immune-related adverse events (irAEs) result in a broad spectrum of clinical events including rheumatic clinical syndromes, which may resemble classic rheumatic diseases. The most common rheumatic manifestations include inflammatory arthritis, myositis, vasculitis, and sicca syndrome. Recognizing rheumatologic irAEs is challenging due to the wide spectrum of clinical presentations that often do not fulfill traditional classification criteria of rheumatic diseases. A delayed diagnosis and treatment can lead to long-term disability, and disorders may become chronic and require ongoing immunosuppressive therapy. The management of irAEs includes the prompt detection and appropriate grading since their management is dictated by their severity. The growing use of CPIs, and the ensuing increase in irAEs, warrants an increasing collaboration between rheumatologists and oncologists. Understanding the pathophysiology, diagnosis, grading, and therapeutic implications of irAEs in patients with cancer is thus a requirement for Latin American oncologists and rheumatologists alike.