Assessment of immune-related rheumatological adverse events in a monovalent oncology center in Argentina

Abstract Background Immune checkpoint inhibitors (ICIs) has changed the outcome of oncology patients. They are being used in an increasingly number of different cancer types. As a consequence, there is an enhance report of toxicity ICIs associated, named immune related adverse events. Herein we focused on the description of the Immune related Rheumatologic Adverse Events (IrRAEs) in oncological patients treated with ICIs, determining the continuity of the oncological treatment following their development, and investigating whether pre-existing rheumatologic disease (PRD) was the reason for not initiating the ICI treatment. Methods it is a descriptive and retrospective study. Included 42 oncology patients, initiating or already undergoing an ICI treatment, who were referred to the Rheumatology Department during 2019–2022. Results 40/159 (25%) patients that received ICI treatment at the Institute of Oncology “Ángel H. Roffo”, were evaluated by the Rheumatology Department. 16/40 experienced IrRAEs. Treatment of IrRAEs: 5/16 received non-steroidal anti-infammatory drugs, 11/16 corticosteroids (5/11 required additionally Disease-Modifying Antirheumatic Drugs (DMARDs). The IrRAEs treatment outcome was complete response (9/16), partial response (2/16) and no response (5/16). As a consequence 7/16 patients (44%) were able to continue the ICI therapy, 3/16 (19%) experienced a temporary suspension and 6/16 (37%) a permanent discontinuation. Two patients did not iniciate ICIs due to PRD. Conclusions 25% of the total ICI treated patients developed rheumatologyc symptoms. The IrRAEs were the cause of them in 16/40 patients. Therefore 10% (16/159) of the total ICI treated patients developed IrRAEs. Most of the IrRAEs observed were mild to moderate. Only one patient, who suffered myositis, experienced a severe life-threatening IrRAE. The patients´ evaluation at the time they started the ICI therapy allowed the diagnosis of PRD and to monitore exacerbations. More than half of the patients who developed IrRAEs were capable to continue their ICI treatment.