Effectiveness and safety of tocilizumab in patients with refractory or severe Takayasu's arteritis: A prospective cohort study in a Chinese population.

OBJECTIVE: To assess the effectiveness and safety of tocilizumab (TCZ) in treating severe/refractory Takayasu's arteritis (TAK). METHODS: A prospective cohort study was started on 1 November 2013 and terminated on 10 June 2020. Thirty-seven patients diagnosed as severe/refractory TAK, treated with TCZ combined with or without immunosuppressors were enrolled. Treatment response (complete remission (CR) and partial remission (PR)), imaging progression and side effects were analyzed at 6-month treatment. Disease flare was analyzed during the remaining follow-up. RESULTS: The CR and RR rates were 70% and 88% at 6 months of TCZ treatment, respectively. Glucocorticoids was tapered from 30.0 (20.0-40.0) to 15.0 (10.0-15.0) mg/day at 6 months. Younger patients (≤26 years) (OR=14.6, 95% CI 1.27-170.4, P<0.05) and those with involvement of bilateral carotid arteries or vertebral arteries (OR=14.6, 95% CI 1.27-169.1, P<0.05) might show a better response to TCZ at 6 months. Combined therapy of immunosuppressors had no significant effects on the effectiveness of TCZ at 6 months. Among the total 23 patients with CR at 6 months, 14 cases discontinued TCZ therapy after 6 months, and disease flare was observed in six ones (43%), with medium flare at 7 (7-9.8) months. One patient (11%) who continued TCZ therapy suffered disease flare at 8 months. Infections were the most commonly observed side effects (38%), with four patients discontinuing TCZ treatment due to severe infections. CONCLUSION: TCZ treatment achieved a favorable response with acceptable adverse effects for TAK.