Real-world risk of relapse of giant cell arteritis treated with tocilizumab: A retrospective analysis of 43 patients

Objective Tocilizumab (TCZ), an IL-6 receptor antagonist, is approved for giant cell arteritis (GCA) as a cortisone-sparing strategy and in refractory patients. This study assessed the real-world efficacy, safety, and long-term outcomes of GCA patients treated with TCZ.

Methods We conducted a multicenter retrospective observational study at three French centers. All patients ≥ 50 years, meeting the American College of Rheumatology (ACR) criteria, and had received at least one dose of TCZ were included. Relapse was defined by therapeutic escalation, such as increased doses of CS, resumption of CS after weaning, or introduction or intensification of adjuvant therapy.

Results Between 2013 and 2019, 43 patients were included. Patients were followed-up in median 511 days between GCA diagnosis and inclusion with 34/43 (72%) patients experiencing relapses. At inclusion, median age was 77 years and median dose of corticosteroid (CS) was 15 mg/day. After inclusion, the mean cumulative dose of CS was 2.1g/year versus 9.4g/year before inclusion (p<2.10⁷) with 12/43 (28%) patients experiencing relapses on TCZ. Among 29 patients undergoing TCZ discontinuation, 18 (62%) experienced relapse. Factors associated with relapse after inclusion were introduction of TCZ > 6 months after diagnosis (p=0,005), absence of ischemic signs at diagnosis (p=0,006), relapse rate >0.8/year (p=0.03) and absence of CS tapering ≤ 5 mg/day (p=0,03) before inclusion. Serious adverse events occurred in 18/43 patients (42%), including four deaths.

Conclusion Our results confirm the effectiveness of TCZ for CS-sparing, but after discontinuation of treatment, TCZ allows for a prolonged remission in less than 50% of patients. Attention must be paid to the tolerance of this long-term treatment in this elderly and heavily treated population.