The effect of tocilizumab on preventing relapses in adult-onset Still's disease: A retrospective, single-center study

Objectives. To investigate the clinical effectiveness of tocilizumab (TCZ), a monoclonal antibody against the interleukin-6 receptor, in preventing relapse in patients with adult-onset Still's disease (AOSD). Methods. This retrospective study included clinical data from 40 patients who underwent regular follow-up at our institution in June 2013. Among these patients, 10 received TCZ. The relapse-free rate was analyzed by the Kaplan-Meier method. Results. The age at disease onset (median, interquartile range [IQR]) was 39 (29-52) years. The duration of disease in June 2013 (median, IQR) was 86 (41-193) months. A total of 87 relapses were documented in 27 patients. Ten patients with refractory or relapsing disease received 8 mg/kg of TCZ every 2-4 weeks. After 6 months of TCZ treatment, the median levels of C-reactive protein significantly decreased from 6.3 to 0.01 mg/dl (p<0.01). Among these 10 patients, 11 relapses were observed before TCZ treatment, and none were observed after the treatment. The relapse-free rate of the 10 patients after starting TCZ was significantly higher than that of all 40 patients after the initial treatments (100% and 67% at 12 months, respectively; p = 0.03). Conclusions. TCZ effectively prevented relapses of AOSD, and it resolved the disease activity.