Randomised, double-blind, placebo-controlled trial of IL1-trap, rilonacept, in systemic sclerosis. A phase I/II biomarker trial.

Objective. This clinical trial was designed to study the safety and efficacy of blocking IL-1 in skin fibrosis of patients with diffuse cutaneous systemic sclerosis (dcSSc), and to test the hypothesis that inhibition of IL-1 by rilonacept will downregulate expression of the 2G SSc gene biomarker as a surrogate for the modified Rodnan skin score (MRSS). Methods. 19 dcSSc patients were randomised 2: 1 active treatment: placebo in this double blinded trial. Study patients received weekly treatments with either subcutaneous rilanocept 320 mg loading dose at day 0 and then 160 mg for each of the 5 subsequent weekly doses, or placebo. Skin biopsies were taken to test 2G SSc biomarker gene expression at day 0 before treatment and one week after the final study drug dose, comparing gene expression changes between rilonacept-and placebo-treated patients, as well as the change in gene expression at week 6 compared to baseline in rilonacept-treated patients. Safety assessments extended to 6 weeks after the final dose of study drug or placebo. Other secondary outcome measures included global and IL-1-regulated gene expression, serum biomarkers and the MRSS. Results. Rilonacept compared to placebo-treated patients did not show any treatment-related effect on the 2G SSc biomarker. Rilonacept treatment also failed to alter IL-6 expression in skin, serum IL-6, C-reactive protein, or CCL18, a marker of IL-6 activity in SSc. Conclusion. In this small trial we did not observe any effect of blocking IL-1 on clinical skin disease or biomarkers of IL-1 activity.