Systematic sclerosis (SS) is an autoimmune disorder characterized by diffuse fibrosis and vascular abnormalities. Although there is no known cure for SS, recent studies have suggested that tocilizumab could be an efficacious treatment. This study aims to examine the safety and efficacy of tocilizumab, an anti-interleukin-6 receptor antibody, in the treatment of SS.

This randomized, multicenter, placebo-controlled, double-blind, phase 3 trial included a total of 210 patients with diffuse cutaneous SS. The patients were randomly assigned in a 1:1 ratio to receive subcutaneous tocilizumab  162 mg (n=104)or placebo (n=106) weekly for 48 weeks. The primary outcome of the study was the difference in change from baseline in the modified Rodnan skin score (mRSS).

The least-square mean (LSM) change in mRSS in the intention-to-treat population was −6.14 for tocilizumab and –4.41 for placebo. The findings favored tocilizumab, with a difference in LSM of 4.2. The most commonly occurring adverse events included infections (52% with tocilizumab and 50% with placebo). Thirteen patients in the tocilizumab group and 18 in the placebo group reported serious adverse events, mainly infections, and cardiac events.

The research concluded that although the primary skin fibrosis endpoint was not met, the findings for the secondary endpoint suggested that tocilizumab could preserve lung function in patients with SS.