Tocilizumab in Giant Cell Arteritis. Observational, Open-label Multicenter Study of 134 Patients in Clinical Practice

Objective: Tocilizumab (TCZ) has shown efficacy in clinical trials on giant cell arteritis (GCA). Real-world data are scarce. Our objective was to assess efficacy and safety of TCZ in unselected patients with GCA in clinical practice Methods: Observational, open-label multicenter study from 40 national referral centers of GCA patients treated with TCZ due to inefficacy or adverse events of previous therapy. Outcomes variables were improvement of clinical features, acute phase reactants, glucocorticoid-sparing effect, prolonged remission and relapses. A comparative study was performed: (a) TCZ route (SC vs. IV); (b) GCA duration (≤6 vs. >6 months); (c) serious infections (with or without); (d) ≤15 vs. >15 mg/day at TCZ onset.

Results: 134 patients; mean age, 73.0 ± 8.8 years. TCZ was started after a median [IQR] time from GCA diagnosis of 13.5 [5.0-33.5] months. Ninety-eight (73.1%) patients had received immunosuppressive agents. After 1 month of TCZ 93.9% experienced clinical improvement. Reduction of CRP from 1.7 [0.4-3.2] to 0.11 [0.05-0.5] mg/dL (p < 0.0001), ESR from 33 [14.5-61] to 6 [2-12] mm/1st hour (p < 0.0001) and decrease in patients with anemia from 16.4% to 3.8% (p < 0.0001) were observed. Regardless of administration route or disease duration, clinical improvement leading to remission at 6, 12, 18, 24 months was observed in 55.5%, 70.4%, 69.2% and 90% of patients. Most relevant adverse side-effect was serious infections (10.6/100 patients-year), associated with higher doses of prednisone during the first three months of therapy.

Conclusion: In clinical practice, TCZ yields a rapid and maintained improvement of refractory GCA. Serious infections appear to be higher than in clinical trials.