Methotrexate pharmacogenetics in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a systemic inflammatory arthritis that can not only result in permanent joint damage, but is associated with high morbidity and mortality. Disease-modifying antirheumatic drugs (DMARDs) are the mainstay of treatment in RA. DMARDs improve the symptoms of joint pain and swelling, but more importantly, prevent the progression of joint damage. Methotrexate (MTX) is the first-line DMARD in RA with over two decades worth of excellent long-term efficacy and safety. However, there is significant variability in patients' response to MTX, both in efficacy and toxicity. Recent advances in genetics, particularly pharmacogenetics, may permit the prediction, a priori, of an individual patient's response to MTX. In this review, we highlight recent published literature on the pharmacogenetics of MTX in RA. Pharmacogenetics may be a useful means of optimising MTX therapy in patients with RA.