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

This study was undertaken to evaluate glucocorticoid dosages and serologic findings in patients with giant cell arteritis (GCA) flares.

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.

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.

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.