Efficacy and safety of tocilizumab in treatment of Takayasu arteritis: A systematic review of randomized controlled trials

Takayasu arteritis (TAK) is a chronic immune vasculitis in which Interleukin-6 (IL-6) receptors play a key role in pathogenesis. Tocilizumab (TCZ), an IL-6 receptor antagonist with a favorable safety and efficacy profile, has been tried as an option for patients with TAK. This systematic review analyzed the evidence from randomized control trials (RCT) assessing the safety and efficacy of TCZ in patients with TAK. MEDLINE, Embase, the Cochrane Library, and clinical trial registries were searched from inception to July 2018. We included RCT assessing the efficacy and safety of TCZ versus placebo/other comparators for the treatment of patients with TAK. The risk of bias (RoB) was assessed using Cochrane RoB tool. 2799 identified articles were screened as per abstract and title; 42 selected full-texts articles were assessed for the potential inclusion. One trial, reported in two publications, comparing subcutaneous TCZ (162 mg/week) versus matching placebo in 36 patients with TAK was included. The relapse-free rate at 24 weeks was 50.6% and 22.9% in TCZ and placebo arm, respectively. The hazard ratio (HR) for time to first relapse was statistically significant in the per-protocol population (HR 0.34 [95.41% CI, 0.11-1.00]; p = .0345), while non-significant in the intention-to-treat population (HR 0.41 [95.41% CI, 0.15-1.10]; p = .0596). The serious adverse events were higher in the placebo arm. This systematic review finds the existing evidence from RCT on efficacy and safety profile of TCZ in TAK to be promising but limited. Additional evidence is required to draw a stronger conclusion.