Treatment of Takayasu arteritis with the IL-6R antibody tocilizumab vs. cyclophosphamide.

OBJECTIVE: To evaluate the treatment effects of the IL-6R antibody tocilizumab and cyclophosphamide (CTX) in patients with Takayasu arteritis (TA) and explore the mechanism by analyzing their effects on various cytokines.

METHODS AND MATERIALS: This study included 9 TA patients treated with tocilizumab, 15 TA patients treated with CTX and 24 healthy controls. Treatment effects were evaluated based on: (1) Kerr score and Indian Takayasu Clinical Activity Score (ITAS2010), (2) improvement of previous lesions and occurrence of new vascular lesions on magnetic resonance angiography (MRA), (3) changes in various cytokine levels, (4) glucocorticoid sparing, and (5) adverse effects. ELISA was used to analyze the cytokine levels.

RESULTS: Before treatment, all the patients had active disease accompanied with elevated C-reactive protein (CRP), serum amyloid A (SAA), interleukin (IL)-6 and pentraxin-3 (PTX3). Moreover, an imbalance in the MMP-TIMP system was also observed in these patients. Among them, IL-6 and MMP-9 levels were significantly associated with vascular enhancement scores and stenosis scores, respectively. At 6months after treatment, improved clinical manifestations and glucocorticoids sparing were observed in both groups without any severe side effects. Although no significant improvement occurred in the vascular stenosis, thickness and enhancement scores in both groups, a more degree of decrease of ESR, CRP level, significantly decreased MMP-9 level and increased MMP-2 level were found in the tocilizumab group than in the CTX group.

CONCLUSIONS: The IL-6R antibody may be more effective in mitigating vascular inflammation and remodeling than CTX via inhibition of IL-6 and MMP-9.