Safety and effectiveness of tocilizumab in systemic sclerosis: a multicentre French-Italian study

Background: Tocilizumab (TCZ) has shown beneficial effects on interstitial lung disease (ILD) in systemic sclerosis (SSc). We aimed to assess the real-life safety and effectiveness of TCZ on several SSc-related domains using data from a French-Italian multicentre cohort. Methods: We conducted a retrospective analysis of patients with SSc treated with TCZ across 15 referral centres. The following clinical data were collected at 12 months before TCZ initiation, at baseline and at 12 and 24 months of treatment: modified Rodnan skin score (mRSS), pulmonary function tests, Disease Activity Score in 28 joints using C reactive protein, digital ulcers and cardiac biomarkers. ILD progression was defined as a decline ≥5 in %predicted forced vital capacity (%pFVC) over 12±3 months. Results: 197 patients were included (88% female; median age 57 years; median disease duration 9 years); 67% were antitopoisomerase I positive. TCZ monotherapy was used in 29% of cases, methotrexate was the most frequent combined treatment (35%). In SSc-associated ILD, %pFVC declined significantly from -12 months to baseline (81% to 77%; p=0.003). On TCZ introduction, %pFVC stabilised and the proportion of progressors declined from 43% to 24% (p=0.015). Among diffuse cutaneous patients, mRSS decreased significantly at 12 and 24 months. Digital ulcers, arthritis activity and cardiac biomarkers also improved. Infections were the most frequent adverse events (22.8%). TCZ was discontinued in 32% of patients, mainly for inefficacy. Pulmonary arterial hypertension and older age predicted TCZ failure, whereas elevated CRP predicted better response. Conclusions: In this large real-life cohort, TCZ was safe and associated with consistent benefits across different domains, supporting its role as a potential disease-modifying treatment in selected patients with SSc.