Effectiveness of tocilizumab without high-dose Glucocorticoids in patients with active Takayasu arteritis：a single center observational study

Background Current guidelines recommend high dose glucocorticoids (GC) as first-line treatment for active Takayasu arteritis (TA) and biologics including tocilizumab as second-line treatment. To minimize or avoid toxicity of GC, it will be beneficial to control TA without GC. This study is to investigate the effectiveness of tocilizumab to induce remission of active TA without synergistic application of high dose GC. Method The clinical data of active TA patients treated by tocilizumab in a single center were analyzed. Disease activity was assessed by NIH score and ITAS-A score. The clinical features of patients who did not achieve remission were compared with that of patients with good response. Results Totally 13 patients with active TA applied tocilizumab to induce remission along with methotrexate (MTX). Among them, 8 treatment-naïve patients did not use GC, 3 relapsed patients maintained 5mg/d prednisone, and 2 patients with inadequate response to conventional treatment tapered the dosage of GC. The acute reactants and TA activity scores were significantly decreased 12 weeks and 24 weeks after tocolizumab and MTX treatment. Ten patients (10/13, 76.9%) achieved remission by TCZ treatment, and most of them did not depend on the effects of GC. Three non-responders subsequently changed their treatment to high-dose GC along with immunosuppressants, but they still showed active disease 24 weeks after treatment. The prevalence of artery area pain of patients (3/3, 100%) who did not respond to tocilizumab was significantly higher than effective patients (2/10, 20%, p = 0.035). The baseline CRP and ESR level in the ineffective patients was significantly higher than that of the effective patients Conclusion Tocilizumab is effective to induce remission of active TA without GC in about three quarters of patients. Pain in the anatomic area of artery and high level of CRP are related to ineffectiveness of tocilizumab. Patients who resistant to tocilizumab treatment are likely refractory to conventional treatment either, and novel therapeutic strategies are required for those patients.