Design and rationale of the Study of Etanercept and Methotrexate in Combination or as Monotherapy in Subjects with Psoriatic Arthritis (SEAM-PsA).

Objective: To evaluate the efficacy of etanercept and methotrexate as monotherapies and as combination therapy in subjects with active psoriatic arthritis (PsA). Methods: The Study of Etanercept and Methotrexate in Combination or as Monotherapy in Subjects with Psoriatic Arthritis (SEAM-PsA) is an ongoing, global, double-blind, 48-week, randomised, controlled study. Subjects are randomised (1:1:1) to etanercept monotherapy, methotrexate monotherapy or etanercept-methotrexate combination therapy. Endpoints include rates of ACR20 response and Minimal Disease Activity, measures to characterise extra-articular manifestations (dactylitis, enthesitis, nail disease) and safety. Conclusion: SEAM-PsA will characterise the effects of etanercept with and without background methotrexate and methotrexate alone on PsA manifestations, and provide information of practical importance to clinicians on the optimal treatment of PsA.