Subcutaneous Versus Intravenous Tocilizumab in Aortitis Associated With Giant Cell Arteritis: Multicenter Study of 196 Patients

Objective Aortitis associated with giant cell arteritis (GCA) is a severe manifestation, potentially leading to aneurysms and aortic dissection. Tocilizumab (TCZ) has demonstrated efficacy in the treatment of GCA, both intravenously or subcutaneously administered. However, pivotal studies did not specifically evaluate aortic involvement, and no comparison of intravenous (IV) versus subcutaneous (SC) TCZ has been performed in patients with GCA‐related aortitis. The objective of this study was to compare the effectiveness of TCZ according to the administration route in patients with GCA‐associated aortitis under clinical practice conditions. Methods This was a multicenter observational study including 196 patients diagnosed with GCA‐associated aortitis by imaging and treated with TCZ. Patients were grouped by administration route: IV or SC. GCA was diagnosed following the 1990 American College of Rheumatology criteria, temporal artery biopsy, and/or vascular imaging. Aortitis was identified using 18 F‐fluorodeoxyglucose positron emission tomography/computed tomography scan. Main outcomes included EULAR remission, clinical and imaging remission, absence of systemic inflammation, and glucocorticoid‐sparing effect. Results Of 196 patients (148 women; mean age 69.8 ± SD 9.4 years), 110 received IV TCZ and 86 SC TCZ. Baseline clinical characteristics and markers of inflammation were comparable between groups. The glucocorticoid‐sparing effect was similar. At 24‐month follow‐up, EULAR‐defined remission was significantly more frequent in the SC group (83.3% vs 80.6%; P < 0.05). However, rates of imaging remission and absence of systemic inflammation were comparable between treatment arms. Conclusions In this real‐world cohort of GCA‐associated aortitis, SC TCZ showed slightly greater effectiveness than IV TCZ in achieving EULAR‐defined remission, whereas no significant differences were observed between both routes regarding imaging remission.