Glucocorticoid Dosages and Acute-Phase Reactant Levels at Giant Cell Arteritis Flare in a Randomized Trial of Tocilizumab

Abstract

Objective: This study was undertaken to evaluate glucocorticoid dosages and serologic findings in patients with giant cell arteritis (GCA) flares. Methods: Patients with GCA were randomly assigned to receive double-blind dosing with either subcutaneous tocilizumab (TCZ) 162 mg weekly plus 26-week prednisone taper (TCZ-QW + Pred-26), every-other-week TCZ plus 26-week prednisone taper (TCZ-Q2W + Pred-26), placebo plus 26-week prednisone taper (PBO + Pred-26), or placebo plus 52-week prednisone taper (PBO + Pred-52). Outcome measures were prednisone dosage, C-reactive protein (CRP) level, and erythrocyte sedimentation rate (ESR) at the time of flare. Results: One hundred patients received TCZ-QW + Pred-26, 49 received TCZ-Q2W + Pred-26, 50 received PBO + Pred-26, and 51 received PBO + Pred-52. Of the 149 TCZ-treated patients, 36 (24%) experienced flare, 23 (64%) of whom were still receiving prednisone (median dosage 2.0 mg/day). Among 101 PBO + Pred–treated patients, 59 (58%) experienced flare, 45 (76%) of whom were receiving prednisone (median dosage 5.0 mg/day). Many flares occurred while patients were taking >10 mg/day prednisone: 9 (25%) in the TCZ groups and 13 (22%) in the placebo groups. Thirty-three flares (92%) in TCZ-treated groups and 20 (34%) in PBO + Pred–treated groups occurred with normal CRP levels. More than half of the PBO + Pred–treated patients had elevated CRP levels without flares. Benefits of the TCZ and prednisone combination over prednisone alone for remission induction were apparent by 8 weeks. Conclusion: Most GCA flares occurred while patients were still receiving prednisone. Acute-phase reactant levels were not reliable indicators of flare in patients treated with TCZ plus prednisone or with prednisone alone. The addition of TCZ to prednisone facilitates earlier GCA control.