Tocilizumab (TCZ) for Giant Cell Arteritis: Clinical Outcomes Following Relapses and TCZ Discontinuation Due to Adverse Events

Objective Tocilizumab (TCZ) is effective for giant cell arteritis (GCA). However, little is known regarding treatment modification and clinical outcomes after unfavorable events such as GCA relapses or TCZ discontinuation due to adverse events (AEs). Methods This multicenter retrospective study included patients with GCA who initiated TCZ from 2008 to 2021 at 5 Japanese hospitals. GCA relapses and TCZ-related AEs were monitored for 2 years after TCZ initiation. In patients with GCA relapses, subsequent clinical courses, including relapse symptoms and treatment modification, were followed for 90 days after the relapses. Similarly, patients who discontinued TCZ because of AEs were additionally followed until 1 year after the TCZ discontinuation to evaluate AEs, relapses, and treatment changes. Results Of 62 eligible patients, 10 patients (16%) relapsed after initiating TCZ therapy. Most relapses (8 of 10) occurred after extending TCZ intervals or discontinuing TCZ. Combinations of adjusting TCZ intervals, adjusting glucocorticoid (GC) dose, and/or adding or increasing methotrexate (MTX) therapy could manage the relapses without serious complications. In the entire cohort, AEs occurred in 28 patients (45%), and 8 patients (13%) discontinued TCZ because of AEs. After AE-related TCZ discontinuation, 6 patients attempted to taper GCs without other immunosuppressive therapy (IST), and 4 subsequently relapsed. In contrast, 2 patients who used other IST or biologic therapy could decrease GCs without relapses. Conclusion Although GCA relapses can occur after initiating TCZ therapy, most relapses can be safely managed by adjusting TCZ, GC, and/or MTX doses. Adding IST or biologic treatments may potentially be related to preventing relapses when patients discontinue TCZ because of AEs.