Evaluation Effects of Treatment With IL-6R Inhibitor on Clinical Response and Biomarkers in Patients With Rheumatoid Arthritis (RA) Not Responding to DMARDs and/or a First Biological Agent.

Inclusion criteria: * Signed informed consent form; * Patients aged 18 - 75 years; * RA classified in compliance with the 2010 ACR/EULAR criteria; * Patients that have to suspend a previous treatment with DMARDs for total ineffectiveness or intolerance to drugs and/or patients that have not responded adequately to first-line combination DMARDs / biological treatment; * Patients for which is indicated to start a treatment with an inhibitor of IL-6R for high values indicative of systemic inflammation (ESR\>=28 mm/hour, PCR\>5 mg/l , Fibrinogen \>400 mg/dl and or Albumin \<3.5 g/dl) and high disease activity (DAS\>2.4), or contraindications to DMARDs use which make it necessary to take biological drug in monotherapy. * Corticosteroids therapy stable (\< = 7.5 mg)for at least four weeks; * Joint symptoms for at least three but no more than 24 months from the screening visit; * DAS44 \>2.4 and/or SDAI \>11 * Willing and able to comply with study procedures and timing. Exclusion criteria: * On going pregnancy or lactation; * Severe active infections; * Patients with other clinically significant concomitant diseases whose treatment or outcome could interfere with the expected evaluations of the study protocol. * Blood AST or ALT levels \>5 times the upper normal limit; * ANC count \<0.5 x 109/L * Platelet count \<50 x103 /μL * Patients with other autoimmune rheumatic diseases, in addition to AR (for example systemic lupus erythematosus \[SLE\], scleroderma, polymyositis, ecc…) * Medical history or concomitant joint diseases in additions to AR (for example tophaceous gout, reactive arthritis, psoriatic arthritis).