Abatacept for systemic lupus erythematosus: the outlook.

Abatacept is a selective T-cell co-stimulation modulator that inhibits full T-cell activation and subsequent antibody production by B cells. Despite the efficacy of abatacept in murine lupus, randomized controlled trials in human SLE do not reveal benefit of abatacept in non-renal and renal lupus. While problems in the study design and the primary efficacy end points may contribute to the negative results of these trials, post hoc analyses using alternative definitions for clinical response suggest the possibility that abatacept may have beneficial effects in active lupus arthritis and proliferative nephritis. Future clinical trials of abatacept should target on defined subsets of SLE patients, utilize multiple pre-defined outcomes based on experience from previous studies and determine the best timing of adding abatacept on a background of minimal immunosuppressive therapies.