Despite availability of various disease-modifying anti-rheumatic drugs (DMARDs) for the management of rheumatoid arthritis (RA), less than a fifth of DMARD-experienced patients receiving anti-tumor necrosis factor (TNF) biologic treatment achieve a 70% improvement in disease activity (American College of Rheumatology [ACR]70 response), even when co-administered with methotrexate (MTX) [1]. This evidence concerns the gene TNF and rheumatoid arthritis.