Selective modulation of T-cell co-stimulation: a novel mode of action for the treatment of rheumatoid arthritis.

Disease-modifying antirheumatic drug therapy, including biological treatments that act via tumour necrosis factor (TNF)-alpha blockade, have benefited numerous patients suffering from rheumatoid arthritis (RA). However, a portion of the patient population is unresponsive to initial therapy, experience a decline in response over time or may develop side effects to treatment. These factors illustrate the requirement for additional therapy options, with novel modes of action, in order to treat this chronic and disabling disease. Activated T cells predominate in the disease processes of RA. Therefore, one rational approach to therapy is to modulate or target T cells. Abatacept is a first-in-class agent that targets T-cell modulation via the co-stimulatory CD80/CD86:CD28 pathway. Preclinical studies and clinical trials have demonstrated both the rationale and efficacy of using T-cell modulation as a therapeutic approach and, as a result, abatacept is currently approved in the European Union for the treatment of RA in adults with moderately to severely active disease who have not responded to TNF-alpha antagon-ist therapy. This review will highlight abatacept as an important treatment option in the therapeutic repertoire for RA that selectively modulates T-cell co-stimulation.