The purpose of this study is to compare the efficacy and safety of adalimumab produced by CinnaGen company and AbbVie adalimumab in subjects with active rheumatoid arthritis. Patients with diagnosis of active rheumatoid arthritis according to EULAR criteria (European League Against Rheumatism) aged between 18 to 75 years are included. This is a Phase III, randomized, two arms, double blind (patient and assessor blinded), parallel active non inferiority controlled clinical trial. The eligible patients are randomized in a 1:1 ratio to receive CinnoRA® or Humira®. Every 2 weeks, 40 mg of either of the drugs is administered to each patient subcutaneously along with methotrexate (15 mg/week), folic acid (1 mg/day), and prednisolone (7.5 mg/day) over a six-month period.