Biomarkers in Rheumatoid Arthritis Treated With Anti-interleukin-6 Therapy

The use of anti-interleukin (IL)-6 therapy, including tocilizumab, in rheumatoid arthritis or giant cell arteritis, led to the improvement or even control of disease in some patients for whom no further therapeutic options were available. Nevertheless, the evaluation of the efficacy of these treatments are negatively impacted by the lack of reliable biomarkers. Indeed, usual inflammatory biomarkers used during the follow-up of these patients to detect persistent disease activity or intercurrent infection, such as C-reactive protein, fibrinogen and procalcitonin, are dependant on IL-6. Thse usual biomarkers cannot therefore be reliably used during anti-IL-6 therapy. Some other experimental biomarkers are totally or partially independent of IL-6, or even of inflammasome, and thus are credible candidates for the follow-up of patients treated with anti-IL-6 therapy. Here investigators propose a controlled, prospective, monocentric, observational study evaluating several biomarkers, usual and experimental, in patients suffering from rheumatoid arthritis treated with anti-IL-6 therapy. This study will include 25 patients suffering from rheumatoid arthritis requiring an anti-IL-6 therapy and 25 healthy controls. In patients suffering from rheumatoid arthritis, usual and experimental biomarkers will be assessed at D0, D15, W24 and W52 from the introduction of anti-IL-6 therapy, or during an intercurrent infection. Investigators thus hypothesized that experimental biomarker levels will still be increased at D15, contrary to usual biomarkers dependant on IL-6 which will be normal whereas rheumatoid arthritis is still active based on usual radiological and clinical criteria, and that all biomarkers will be normal a W24.