Study Design & Objectives:||Multi-centre, non-interventional, open-label, non-comparative, prospective cohort study with a clinical follow-up between 12 and 14 weeks.||To determine the performances of the RA-INF-Dx blood test intended to aid in the identification of patients with rheumatoid arthritis who are unlikely to show an initial response to infliximab and methotrexate combination therapy evaluated according to EULAR response criteria.||Ancillary study objective:||To constitute a biocollection of samples associated with all clinical and biological data collected at inclusion and at the evaluation visit.